Firebird Mess85

I just picked up my 85 Firebird about a month ago or so and I knew it needed some work when I bought it. I've got some overheating issues. Let me give you guys the background.

The car was a 2.8 V6 that somebody swapped out an LG4 305 in (most likely 1987 with centerbolt heads). I have absolutly no idea if the person that did this knew what they were doing but the car runs and I drove it quite a ways to get it to my house. There is a lot of stuff disconnected like some vaccuum lines and certain sensors. It's carborated with the Roch Quadrajet but the secondary does not work so its basically running like a 2bbl. It's running rich and the idle speed is too fast but I can't get it down anymore. The timing is off but I tried fixing that yesterday but the car got way too hot to do anything. I believe one of the vaccuum hoses that is disconnected is one that goes to the MAP sensor and I do have a check engine light on. It's a code 12 and I believe it's because of the MAP sensor not reading any RPMs.

Also, I was told that the car may have sat for about 10 years.

I flushed the coolant and replaced the thermostat with a 180* failsafe as there wasn't any thermostat in it before, and also replaced the hoses to the radiator because the hose that connected to the waterpump blew off and I had coolant everywhere.

I just have the car idling and it gets very very hot after about 5 minutes.

Any help is appreciated. I just need to get this car running right before I put any money into performance mods.

AlkyIROC

Could be any number of things. Plugged rad, thermostat upside down, bad head gasket, cracked head.

Go a compression and leakdown test first.

Firebird Mess85

The thermostat is deffinatly not in upsidedown and the radiator isn't plugged. I checked both those already. I'm not getting any coolant in my oil but I know that's not the only sign of a bad head gasket. If I had a cracked head wouldn't I be getting oil everywhere?

I can't do a compression test yet because I had to tap the thermostat housing and intake because there was no thread and I couldn't screw one of the bolts down when I put the thermostat in and now it's not completely snug and I'm leaking a little bit of water out of where that screw is. If I run a compression test now I think it might possibly give me false results.

calamitascamaro

iTrader: (5)

How fast does it warm up? Does it go right to over heat? Or linger slowly till it does..... Do you have a heater core still? Does your fan kick on and off, or is it hard wired?

ezysk

Some other items to check.
Old catalytic converter causing higher than normal backpressure.
There is also a preheater assembly on the passenger side exhaust manifold between the Y-Pipe and the manifold itself. There is a butterfly plate in there that sometimes rusts in a mostly shut position, especially if the car sat for a while. I would check that out.
Finally, make sure they didn’t use the Y-Pipe off the 2.8 V6 for the 305, which again would cause restrictions and heat.

Easiest way to test all that, if you live in an area that is more tolerant of noise is drop the Y-Pipe, and start her up to see if it still overheats.

AlkyIROC

Not plugged through the fins but plugged inside the core preventing proper coolant flow through the rad.

Doing a cylinder compression test doesn't matter if you have an intake on or not. You're just checking to see what kind of pressure builds up in the cylinder.

Batass

Open the rad cap BEFORE you start the motor, then start it and see if the coolant sucks down and moves. You might have to wait a couple minutes for the thermostat to open to see much movement.

Also, the gauges in these cars are ****. It could just be a bad gauge. Mine went up to 250 once and I was worried, then my buddy grabbed the coolant hose and said, hey sunshine, there's no way its 250*.

steeljab

iTrader: (3)

my fan doesn't work, so its does that sitting still...but keep it moving and its fine....might wanna check that

Firebird Mess85

I did thisan there is coolant moving. I don't have a temp guage, just a dummy light that shows a temp. light.

Here's what I did tonight and it might give some more insight. I stopped at Advance Auto and got a coolant flush bottle that said it'd remove deposits, rust, etc. The bottle said to pour the bottle in the radiator, then to top off with water. I did so....The next step was to run the car untill at normal operating and then turn the heater on high with the engine on for 10 minutes. Then let the engine cool down and drain the radiator.

I ran the engine for 10 mins with the heater on high and all the while that screw I told you about earlier had water/cleaner mix seaping out a bit. The engine was very hot and the Temp. light was on at the end of the 10 mins. All of the hoses were very very hot and even while the engine was off the water/cleaner mix was still seeping out of the screw by the thermostat housing/intake. During this time while the engine was off and seeping I used a towel to remove the radiator cap because it was so hot and still seeping by the housing and when I did so I managed to get heat and chemical burns on my face cuz the water/cleaner mix spewed out at such a high pressure that it flew up and over my neighbors fence behind me and managed to hit me a bit. I'm begining to think that maybe something is clogged because that was a TON of pressure. Oh, and all the meanwhile that the car was running for 10 mins, the electric fan never went on at all. I was going to run the fan to a switch but that didn't happen cuz of the burns I incurred.

AlkyIROC

That much pressure in the cooling system tells me you have a bad head gasket.

blackandgoldl69

LoL i did that once when i was 15 coolant went every where then i read the radiator cap and it says never open when hot contents under presssure i felt like an idiot

Batass

Hehe, happened to me too but it was my "mechanic" mustang buddy that opened it on his car. Burned the ***** out of both of us.

Well obviously you need to get that fan working.

Generally I thought, that if you had a blown head gasket, once you start the motor, the coolant would push out the cap hole?

Firebird Mess85

Ha, I've read the cap before. I was only trying to loosen the cap so to let some of the water out and there was so much pressure that it blew the cap off. I had my had over the cap with a towel and there was so much pressure I couldn't hold it down and I think the cap is now in my neighbor's back yard.

Bad head gasket for sure? I keep getting people telling me that it is and couldn't be and it's really confusing. I"m not sure if the guy who did the motor swap before me just didn't hook up some stuff wrong because I've found some errors before.

Oh, another thing that might be of interest that I noticed was that the hose to the water pump from the radiator, and the inlet and outlet hoses from the heater all got hot quickly first while the hose from the thermostat to the radiator was pretty cool within the first couple mins of start up. I do have a 180* failsafe thermostat in there so I'm assuming the thermostat would be open most the time right?

ezysk

It can get confusing especially since everyone and their brother seems to be an arm chair mechanic at times. So you will get some good advice and some bad advice.
So far it looks like most of these posts make since to what it could be.

If you wish to simplify the process, then create a checklist with all the possibilities you have seen so far, Then go through the list testing each one to see if you can rule out anything.

Eventually you will find the issue.

Plus, one very important thing that has been skipped is, how did you determine the car was over heating. I had a cousin that for sure, swore up and down that a Camaro he had was over heating because it would get to 210. Even after I showed him in the service manual that in his year car the fan does not even kick on till 235. According to GM he was in the operating range of the vehicle, but he had a few buddies that didn’t own a third gen that thought that was too hot so he even argued with the GM service manual.

These cars were designed to run hot to help cut down emissions.
Though ideally you can get more power out of it, if you can get it to run a bit cooler.

That is why I ask, what do you qualify as over heating?
Is it a temperature that you see on the gauge, or steam blowing out of your rad when the cap is still on?

This might totally help the trouble shooting.

Firebird Mess85

The temperature light comes on. Thats one reason. The second is that that I can't even touch the hoses they get so hot so quick. Ha ha, also, the water burning me sorta told me it's very very hot and has a lot of pressure very very quickly. There has to be something wrong.

The reason I started replacing the hoses in the first place wasn't because of overheating, but because the hose that connects to the water pump blew off on during a drive one time where the clamp is by the water pump and anti-freeze went everywhere. I noticed the very hot running engine a few days before this but didn't think much of it.

Batass

I think I would pull out the thermostat, and see how it does.

AlkyIROC

A dual fan system, the first fan should kick in at 205. The second fan should kick in at 235. At 235, the engine is getting too hot.

Firebird Mess85

I FOUND THE AREA WHERE THE PROBLEM IS!!!!!

I isolated an area and found out where the problem is, but still don't know what the problem is.

So the hose from the firewall that connects to some vaccuum module and theres another hose from there into the block that is the problem.

I disconnected the hose that went into the firewall from the vaccuum piece because that was the one that gets hot first. The module piece is an outlet from the block and water was coming out of it while disconnected with the engine started. I had a hose putting water in the radiator while the car was running so I wouldn't run out. Ther car didn't over heat while I had that one hose disconected.

Unfortunatly I can't run the car like that because it's just spraying water out onto the ground. Where does that hose that goes into the firewall go to? The heater core? I had the heater on while it was disconected and got no heat so I'm assuming so but don't know for sure. I'm guessing that's where the pressure was coming from too but what would cause the blockage and where would it be?

Just to clarify too, it's the hose on the left looking at the firewall from the front of the car that I disconected.

AlkyIROC

A plugged heater core won't cause it to overheat. Disconnecting the heater hose and using a hose to fill the rad won't cause it to overheat also. You're feeding cold water into an unpressurized cooling system. There's no way for it to overheat like that.

Stop guessing and do some proper troubleshooting.

Fill the cooling system up and start the engine with the rad cap off. Does coolant get pushed out of the rad?

Do a compression test and a cylinder leak test.

If none of those tests show anything, install a new water pump, thermostat and rad.

Batass

Its possible the thermostat is stuck or installed wrong. The return coolant could be NOW flowing out the heater hose.

Does the hose that runs from the intake manifold to the rad get hot? If not replace/fix the thermostat.

Firebird Mess85

[quote=Stephen 87 IROC;3818808]A plugged heater core won't cause it to overheat. Disconnecting the heater hose and using a hose to fill the rad won't cause it to overheat also.
[quote]


I think you misread my post. It DIDN'T overheat when I did disconected the heater hose and used the hose to fill the radiator. The car ran better and cooler and there wasn't all of the pressure I was getting before with that hose connected.


[quote=Stephen 87 IROC;3818808]
Fill the cooling system up and start the engine with the rad cap off. Does coolant get pushed out of the rad?
[quote]

I've done this before and the engine gets very hot real quick.
Yes, the coolant gets pushed out of the radiator. It got boiling and had so much pressure built up that it was spewing up over the side of the car.


[quote=Stephen 87 IROC;3818808] Stop guessing and do some proper troubleshooting. .....Do a compression test and a cylinder leak test.[quote]

I've been trying to get the car running long enough without overheating to do this. I have the get the car into work to do a compression test and I can't drive it with it overheating like this.

...And about Batass' post...yes, the hose that runs from the intake to the rad does get hot.

AlkyIROC

That's exactly what I said. You have the rad cap off and a hose filling the cooling system while it drains from the heater hose. It will be impossible for any engine to overheat in that situation because it's not a closed system and it's constantly being replenished with cold water.

Don't take the rad cap off when it's already hot. When the system is cold, take the rad cap off and start the engine. If coolant instantly gets pushed out, you have compression going into the cooling system. Only a compression test and cylinder leak test will pinpoint where it's coming from. As I said before, you either have a bad heat gasket or a cracked head and maybe a cracked block. If the engine has gotten that hot, there's probably a lot more wrong with it now like cooked seals and gaskets.

Batass

Coolant spews out with the cap off and motor "cold"? Thats absolutely a bad head gasket or a crack.

Oh well, do another swap, this time put a GOOD motor in it, hehe. Hell, your going to spend as much in gaskets to fix it as you could pick up a 350 for, almost.

Firebird Mess85

Looks like I misinterpreted your post and we were actually on the same page.

I took the cap off once when hot and did what you refered to once also...taking the cap off when cold and then starting the engine. When the fluid spewed out it wasn't instantly with a cold engine it was after about 5 mins or so while I was trying to get a read on the timing.

I'm all for putting new heads incase it's warped and new gaskets if that's what needs to be done. I'd do an engine swap also. My gripe with that is getting another engine could just be another problem engine. I don't have the money for a new engine so it'd have to be used.

How much would it cost for gaskets that I could pick up a 350 for close to the cost? If thats the best option I guess I'll do a 350 but I really thought it'd be cheaper to rebuild my current engine.

Batass

It would be cheaper to keep your current engine. I'm guessing the motor is old, so it will need head, intake, header gaskets. Good ones will run close to 100 bucks I believe. There are cheaper ones. Its a good bit of work to remove the head/heads if your unlucky on the first one...once you do that, your not far from completely removing the engine.

Its a lot of work, and while all that is off/out might as well clean it up and inspect stuff. It can be a tough decision.

Firebird Mess85

Does anybody have any experience with K&W Nanotechnology? Does it work or just a bunch of BS?

I was planning on putting a new intake and headers on anyways so I just just do new heads too. Any suggestions for these things? Would the HO 305 intake work good or should I just got with an Edelbrock Performer intake? I'm looking at both right now.

Firebird Mess85

For testing purposes I've just been running water in there. I've flushed the system numerous times. Everything is flowing. Again tonight I ran the car with the radiator cap open and I saw the water flowing fine. I felt the hose coming from the thermostat to the radiator and it was cool while the other hoses were warming and then the thermostat opened and the hose did get hot.


Here's the interesting thing I did tonight that I never did before. A friend had his 88 Camaro with a 305 in it over tonight and it does run on the warmer side. His car has a temp guage and my car doesn't, but his car was running at 225* when driving. Only difference between our engines is that mines carb'd and his is fuel injected and some hose placements and pully order.


Anyways...I had the cap open while the car was running and had a digital thermometer in the opening. The temperature light by the guages went on when the thermometer said about 195* and then at about 205* started spewing water out of the radiator cap hole. I have no difference if the water at the top of the radiator where the cap is would be cooler than the coolant in the engine or not. Maybe the coolant in the engine is 225*???

Batass

1. The temp of the coolant near the cap where you measured is going to be the coolest.

2. The spewing could be from the fact that water boils at 210* I believe, with antifreeze its higher, but the coolant entering the rad is higher than what you measured. When water is under pressure, it raises its boiling point. This is why high up in the mountains, water will boil at a lower temp, and in a vaccum, water boils very quickly.

Anyway, I think the first thing you should do now is get an aftermarket temp gauge and sender. Factory one should be on the driver side in the head.

I dont remember if you've mentioned this earlier or not, but is anything going on in your overflow tank?

Firebird Mess85

I did buy an aftermarket guage setup but it wouldn't work with the car. I found the sender by the head that you mentioned but the temp guage wouldn't work with it. The instructions mentioned something about possibly needing an adapter that the company didn't even make so I returned it.

The only thing going on in the overflow tank is that when it gets hot water is going from the radiator to the overflow tank.

Batass

I would get a new sender and gauge. Its a pretty important thing, especially for your car without a gauge.

How much coolant is transfering over? Now that you know the coolant is flowing, it really only leaves a bad head gasket/crack, or scummed up walls. It would be helpful to actually KNOW what temperature you are at before you start tearing into things.

You should also do a compression test like Stephen said.

Firebird Mess85

I have no idea how much is actually transfering over. I wasn't paying attention to that as much as the temperature.

Any suggestions on a guage that will work with the OEM sensor?

Batass

Id buy a new mechanical sender/gauge kit. I dont know what will work with the stock sender.

Firebird Mess85

Scummed up wall? Didn't know what you meant by that? Just in the heads or the block itself?

Batass

Crap that covers everything. Really old anitfreeze that breaks down and sticks to stuff, minerals from hard water over time, I've seen some really bad ones.

If you don't know what I'm talking about then this isnt your problem.

Firebird Mess85

Eh, I think I know what you mean but don't think at least that I've got that.

I installed a switch to turn on and off the fan. After that I drove the car down the street to a shop. Didn't overheat that far at least but it was only about a 1/4 mile down the road. I dropped the car off at the shop so they can test for a bad head gasket since most of the responses seem to favor that diagnosis. I should know tomorrow hopefully. Sucks paying more for the shop fees than I would at work but I'm sick of wondering what the hell it is.

Batass

I'm guessing they're going to do a cooling system pressurization first, and compression check second.

Let us know what the result is.

Firebird Mess85

Results are in!..... It's not a head gasket. Back to being clueless...

Batass

How do they know? Did they have any other suggestions?

If I was in this situation, I would run some coolant flush through the system, then replace the thermostat with a 180*. Your radiator could be a little plugged up.

Are you running any underdrive pulleys?

AlkyIROC

"not a head gasket" based on what tests and results?

If your engine got that hot, I'd be changing both rad hoses, thermostat, rad cap, water pump and rad anyway. Too much heat is bad for the seals. Test the fan switches to make sure they turn the fans on since you know the fans already work by installing a manual switch.

Firebird Mess85

They did a CO2 test over the radiator three times, when the engine was cold, warm, and hot and all three tests showed nothing. This is the same test the mechanic at work was going to do but he was out of dye for it. Mechanics at both shops said its the second most reliable test they have aside from a leak down test.

I do have a 180* thermostat and I'm not running any underdrive pullys that I know of. Only accesories I know of are the alternator, water pump, power steering pump, and the emissions thing.

I did change both radiator hoses already. I'm thinking you might be right Stephen, I might just be better off changing the radiator and water pump even though they look like their working. Can't hurt anything right?

TZFBird

You are 100% sure you have the timing set to at least 0* base timing, and your advance or vacuum advance is working correctly? I've been down the road of incorrect ignition causing a lot of extra heat. Had to run radiator fan, and heater at the same time in the summer to keep it below 220, when it never did that when I first got the car.
While you have the car running and you gas it, do you hear any detonation that could be an indication of either timing way off, or oil/water in cylinder, maybe a compression difference. Have you pulled the plugs? I would think there might be a slight difference in one that is running in a faulty cylinder if it is in fact a head or head gasket problem.

Did you ever do anything with the exhaust to see if that was flowing freely? I don't know if the 2.8 exhaust would make that much of a difference just at idle, but whatever that was about a baffle in there would surely cause some issues.

Firebird Mess85

The timing is messed up, I know that. I believe the timing is suppposed to be at 6* before TDC, correct? This is my first car older car like this so you'll have to excuse the dumb question but what is advance and vaccuum advance? I have no idea regarding this because I don't know what it is/does.

I haven't done anything with the exhaust. How do I know if it's the 2.8 exhaust system on there?

What would the detonation sound like that I'm listening for?

TZFBird

I have TBI on my car, but the ECM advances the timing to something like 24* after the base timing is set to 0* even at the balancer. I have not worked on anything with a carb, so I am not sure if it has the timing advance bypass that the EFI ones have. In my case, I turn the car off, disconnect the timing advance wire. After that, I can adjust base timing with a timing light on the timing mark at the balancer. You would need to do a bit of research. You might not have anything like that and would just set your timing by means of the timing light.

If you have a computer for your engine... I think the ones in the 80's with carb might have had something like that. You said you have a MAP sesor, so there might be something in the ECM for timing. Otherwise there is probably a vacuum advance that will advance your timing as the vacuum changes. So, say you are running at wide open throttle. The vacuum advance will either retard or advance the timing at the distributor based upon how it is set up and the vacuum that the engine is producing. There again you would need to do some research as to setting that up to work propperly.

You said the car originally came with a V6 and someone had swapped in a 305. I know the exhaust on the cars that came with 305's was pretty small, about 2.5" would be my guess, maybe even 2". I can't remember, it's been quite a while since I pulled all mine off. If the V6 cars had pipes smaller than that, that could be putting a lot of restriction on the engine, causing it to work that much harder to get rid of the exhaust.

Detonation can be very minimal, only detected by a sensor, or as bad as I have had to where you can hear it while driving. I would have a hard time trying to think of something common that it sounds like. I had it real bad and it pretty much sounded like a handful of small rocks being slowly swirled around in a ceramic pot. Of course it's not constant and can come and go with load and rpm. Just because you cannot hear it does not mean it is not there with some sort of side-effect.

Firebird Mess85

I don't have a vacuum advance, I had my dad take a look at the car.

Yes I do have a MAP sensor but whoever did the engine swap disconnected the vacuum line that goes to it. So I'm not sure if the V6 had it and the 305 doesn't.

I'll double check the exhaust and see how big the piping is.

BASSETT IROC 85

iTrader: (2)

Intake gaskets upside down? If someone swaped the engine they are prob. not using the computer.

Rayzor32

iTrader: (1)

try taking the thermostat out see if that does anything

RED86Z28

You need to sort out all the disconnected crap under the hood. Is the distributor and carb connected to the computer?

Firebird Mess85

Pretty sure it's connected to the computer. The carb has everything plugged in and it routes back towards the firewall.