Bubbajones_ya

I've researched things about this for quite some time now and thought I could sort things out on my own, however I'm not sure if I can anymore.

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Background Info
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My car is a 1991 305 TBI.

I know these cars run hot normally, but I think mine is running a little hotter than it should, especially with all the work I've recently done.

Before I did any work to my car, on a hot day with city driving (AZ summer especially with the AC on) my cars temps would slowly but continuously climb. If they AC was on, they would go up to 250 or higher if I was going slower than 30-40.

On the highway, it seemed to stay under 225. However, after getting off the highway, my gauge would usually go up to around 230 pretty quickly and every time I got out and checked with temps at or above that, the coolant was boiling into the reservoir.

I did have a big intake manifold leak, and thought maybe my single fan motor was going out.

Recently I did a major engine overhaul (mainly to fix the intake manifold coolant leak), and have changed some other coolant parts recently. The work I did was:

- New camshaft elgin 1136
- New edelbrock performer intake
- cylinder heads checked and resurfaced and valve job
- ultimate TBI upgrades (and 350 injectors)
- new timing chain
- new seal all around

- new water pump
- installed dual fan setup (from TPI) with separate relay to control second fan

recently have done:

- new radiator
- 180 degree thermostat

I also do have these installed:

- The lower air damn
- Air ducts between the front grill and condenser/radiator (the condenser is also new so there is no stuck debris in it)

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Currently:
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I do have the EBL setup so I can tune some stuff for the new parts, but I'm not great at it. However, with some incredible help from another member on this forum (Fast355), I have got my car running decently enough after the new cam and stuff for now with a tune but it still needs work.


HOWEVER, a big reason to do all this work was to try and tackle this cooling issue once and for all.

Today, when idling after about a 10 minute drive, (the ambient temps around were only in the low 90s) my temperature gauge started to read up to 241 on the gauge. My friend has a infrared temp gauge and it said my temps were 237 at the bottom of the thermostat housing.

I did have BOTH fans running at this time. The coolant was not coming out from where it would go into the reservoir though(I have not installed it back yet my old one was broken)

With the AC off and heater on, the temps on my gauge went down to around 215-220.

I checked my coolant level later when the engine cooled down and it was full.

I'm not really sure what to check next or what may be the issue. Driving around tonight my temps were reading around 210-220, but I know during the day they will read much higher.

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Questions I have:
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Does anybody know anything I may have missed that could be causing my car to run hot still? Is the standard auto parts replacement radiator not good enough maybe?

Are there stock fan shrouds for these cars, and if so can someone show me a picture of them? My old single fan setup and the dual fan setup I currently have both have the upper and lower brackets, and fan mounting brackets, but there doesn't seem to have been a shroud for them. Also with my friends camaro and other ones I've seen in the junk yards, I've never noticed a shroud per say.

Are there any "tricks" to help the camaro run a little cooler normally other than install a lower thermostat (like the 180 degree one I have)?




Thank you for any advice and help. My car never overheated during the winter, but during the last two summers its overheats when it gets around 95+ degrees out. It still seems like that is going to happen with my car even after all the new work I've done.

SbFormula

• Do your fans move air from outside to inside engine bay?
• Have you tested your new thermostat in hot water? You could remove it and see if it improves cooling condition.
• Does your new pump circulate the coolant in the right direction?
• Is your radiator clogged?
• Is your radiator cap in good condition, might want to put a new one anyway.

If coolant circulates properly and your fans are ok, you should have all hoses and the radiator superhot too. This would mean your cooling system is insufficient to remove heat from your engine.

If it's the case, it could be that your engine runs too lean which creates lots of heat in the chambers. But that is just a guess. You would need an AFR gauge to see what's going on as far as rich/lean condition goes. I don't know your set up, but is the 02 sensor in the right place?

Best of luck!

naf

iTrader: (7)

A motor that isn't tuned properly will run hot. Either rich or lean, it's not burning the fuel it's getting efficiently and the lost energy is spent as heat.

Tune it, then tackle the overheat problem if you still have one.

Bubbajones_ya

Thank you for the replies! I'm going to continue tuning it and hope things get better. I've never tuned anything before so this is a big learning experience for me, but I am getting some great help on these forums.

As for the other questions,

- My fans do pull air from the radiator/condenser
- I have not tested my thermostat so I may do that or purchase a high quality one. I believe I bought a cheaper thermostat last time
- My pump is this one http://www.summitracing.com/parts/EMP-13123 so I believe it's the correct rotation, it says counterclockwise pump rotation
- I don't know if the radiator is clogged or not. When the cap off and engine running (before it gets totally warmed up), I can see coolant circulating through it
- My radiator cap was purchased with the new radiator, but they are cheap so I may purchase a new one anyways

Thanks again for the help and once I get some more tuning done I'll post back with more results.

Stauf

iTrader: (2)

I would check 2 things first...

Water pump flow direction

Clogged radiator.

I have a 91 305 TPI and I rarely go above 180 degrees in normal driving. There are a few times that I hit over 200, but that is in traffic and ambient temps close to 90.

-=Z28=-

iTrader: (3)

Start with easy stuff first. Just cause your fans are making noise, doesn't mean they are moving air and in the correct direction.

250* is pretty friggen hot.

Try turning your heat on high and see how much that changes it. Sounds like you are close to keeping it at a steady 220, which is around where they run.

I'd start with the fans. A good set of properly wired fans will keep just about anything cool.

Bubbajones_ya

Well I tried doing some dataloggin and VE learns with the EBL system today, but noticed a problem.

My car ended up getting about 230 degrees when coasting after a drive, so I wanted to check the fans after pulling over.

Once of my spark plug wires was off probably the entire time I've been tuning so I bet that has been throwing things off greatly...

Both my fans were running and pulling the air threw the radiator, not blowing, so that should be good.

I double checked and I have a reverse flow water pump so that should be the correct direction for the serpentine setup.

Once I fix the plug wire issue and do more tuning, I'll see if it helps my car run cooler.

SbFormula

Where is your 02 sensor positioned? I ask because I don't want to assume. This is important because if it has been modified and incorrectly position on the exhaust system, the ECM will calibrate the AFR based on incorrect readings. An AFR gauge would be of great help for tuning not to say essential. That would really tell you what's going on with your tuning.

Are you running the OEM multec injectors?

Cheers!

Bubbajones_ya

My O2 sensor is located on the headers right where the four tubes collect on the driver's side. They are the hooker 2055 headers, and I had them ceramic coated too.

I only have a stock single wire style O2 sensor, not a heated one, but it's been replaced within the year, and I read that because my headers are coated, a heated sensor wouldn't make much of a difference.

I believe the EBL tuning program lets me know the AFR (it displays tons of information off my laptop while I'm driving), but I could be wrong there. I will check that out in a little bit to see. The EBL system gets its information from my computer directly, would an aftermarket AFR gauge be better for getting the ratio?

Also with the injectors, I purchased cleaned and flow matched stock TBI injectors for a 350 engine (mines a 305.) They should be OEM ones.


Thanks again everyone for all the information, hopefully I can get this car cooled down soon! It is drive-able.. just on the verge of being too hot.

SbFormula

[QUOTE=Bubbajones_ya;5959726]My O2 sensor is located on the headers right where the four tubes collect on the driver's side. They are the hooker 2055 headers, and I had them ceramic coated too.

I only have a stock single wire style O2 sensor, not a heated one, but it's been replaced within the year, and I read that because my headers are coated, a heated sensor wouldn't make much of a difference.

Perfect!

I believe the EBL tuning program lets me know the AFR (it displays tons of information off my laptop while I'm driving), but I could be wrong there. I will check that out in a little bit to see. The EBL system gets its information from my computer directly, would an aftermarket AFR gauge be better for getting the ratio?

The EBL lets you know the commanded AFR, not the real AFR. The commanded AFR is used by the EBL to calculate injector BPW. The 02 sensor sends feed back to EBL so it can adjust injector BPW based on real AFR. The EBL is attempting to achieve the 02 voltage targets that are programmed in your .BIN. Theoretical stoichiometric combustion is .450V. So if the 02 targets are programmed at .450V, the EBL, in a perfect world, should adjust injector BPW to achieve stoichiometric of 14.7:1 with gasoline without ethanol. An AFR gauge would tell you the actual AFR from the exhaust.

Also with the injectors, I purchased cleaned and flow matched stock TBI injectors for a 350 engine (mines a 305.) They should be OEM ones.

If you have injectors for 350 and your engine is 305, you have to change the injector flow in your .bin. Otherwise you will end up too rich but EBL could probably compensate through BLM correction.

Bubbajones_ya

Thank you for all the useful information!

I'll look into AFR gauges then and see if there is an affordable one I can get! (I took off work for this semester in college because it's my senior year of mechanical engineering so I'm on a tighter budget)

I did use the EBL utility that calculates changes needed in two different tables, BPC -BPC vs vac, and BST - BPC vs Boost tables based on my new injectors and fuel pressure. (I don't know for sure but believe the injectors I got would be 61lbs of presure being they should be stock 350 tbi injectors)

I'm not sure if there are any other tables needed to change based on the injectors though. As a side note for tuning, my one spark plug wire that fell off is so bad it's hard to keep it from arcing against anything so it's going to be hard to tune until my new set comes in. Hopefully they come in tomorrow along with the valve cover wire looms.



Yesterday when driving around in town, my car's gauge was reading in the 230s to and a little higher. To me, the middle "air duct" thing between the front bump/ground effect and radiator seems like it blocks flow from the radiator, so I took that piece off. I kept the air damn (the vertical piece directly under the radiator) on because that seems important.

When I took out the middle air duct, there was a lower piece that is directly bolted on the ground effects I left on. However that part wasn't actually bolted on my ground effects, so when I drove around, it folded backwards and basically blocked airflow up to the radiator. Needless to say, it got a lot hotter when driving, especially on the highway. I ended up figuring that out today and making sure it's bolted in place so it won't do that again.



However, when driving today, I noticed a discrepancy in the coolant temperatures VS computer temperatures. Within the EBL system, it displays the IAC temps and the CTS temps. When my gauge was reading 240 degrees Fahrenheit, the EBL CTS degrees were around 214 Fahrenheit. I do have an aftermarket LED instrument cluster by Intellitronix and they provided a new temperature sending unit that I have mounted on my thermostat housing.

Is it possible for the CTS and temperature sending unit to have such a large difference in temperatures? Or is it possible that one of them is reading incorrectly? I would think the the temp sending unit is reading more correctly since I verified the temperature was close with my friend's heat gun just last week. Before I bought my car (purchased in August of last year), the previous owner said he put in a new CTS, so I never thought about changing it.

SbFormula

I did use the EBL utility that calculates changes needed in two different tables, BPC -BPC vs vac, and BST - BPC vs Boost tables based on my new injectors and fuel pressure. (I don't know for sure but believe the injectors I got would be 61lbs of presure being they should be stock 350 tbi injectors)

I would not know anything about that. I work with CATS RT and on TPI. RBob would be the mastermind. 61lbs of pressure seems high for a TBI.

When my gauge was reading 240 degrees Fahrenheit, the EBL CTS degrees were around 214 Fahrenheit. I do have an aftermarket LED instrument cluster by Intellitronix and they provided a new temperature sending unit that I have mounted on my thermostat housing.

That is interesting! Are the 2 sensors close to each other on the intake? It seems to be quite the difference. Mine has a difference of maximum 10DegF but my dash gauge sensor is on the head driver's side and the CTS in on the intake front near thermostat. The dash always reads lower. I also have a third one (Autometer) in the thermostat housing which is always in line with what the ECM reads. If your 2 sensors are in the same area, such a difference should be investigated.

The picture is for a TPI

Bubbajones_ya

Sorry my fuel pressure is about 11-12 right now, but the flow rate of the injectors is rated at 61 lbs I believe.

As for the location of the temperatures sensrors, the CTS is almost exactly where yours is, but its mounted on top, instead of the side, of the intake manifold, and the temperature sending unit is mounted on top of the thermostat housing which is in the same place as yours.


Again after driving around some, my temp gauge reads about 240, and the EBL is telling my my CTS is at 218.... 218 still seems a little warm though for dual fans and a 180 thermostat.

SbFormula

ummm!!

I don't know where you live, but here in my neck of the woods, if the outside temp is 90DegF, I will reach 203DegF with a 180DegF Thermostat and fan set to start at 193DegF. This is driving at low speed no idling in traffic. The OEM set up was set up to start at 225DegC with a 195DegF Thermostat.

I don't know what your setup is. Maybe your custom digital dash is off. You could try to change your CTS to be sure.

Cheers

Bubbajones_ya

Thanks again for all the information and insight!

I live in Arizona, and while it's been a lot cooler recently, it still around mid 90s in the outside temps.

I think I may get a new coolant temperature sensor soon just to be safe. Right now, I'm re adjusting my valves (because I think I left them a little loose initially tightening them after the engine install) and then am going to put my new plug wires with the expensive looms I bought so they will never burn up again!


I did block off the overflow tank because I have not yet installed my aftermarket tank I bought (which may be a good idea..), and didn't want coolant spraying all over the place. I'm not sure if having that plugged up will cause cooling issues, but I know it seemed to have mess with the pressure, at least after the car has been turned off. After about an hour of my car cooling down today from driving, the upper hose was partially collapsed. After I took the radiator cap off, it shaped back up.

SbFormula

Not too sure about that one, but that would build the pressure pretty hard without the tank. The coolant needs to expand. Not recommended.

Bubbajones_ya

Yeah I didn't plan on having it long like that and then with the other issues I was having I forgot I kept it plugged. I just installed the aftermarket coolant overflow tank which will be hidden in front of the condenser underneath the black plastic cover.

I was trying to test my new plugs and one of them came off and started arcing on the headers.....

I have it even more secured now so it better NEVER fall off! I swear these spark plug wires are afraid of igniting my cylinders. Hopefully I don't have any more arcing issues, and can start to get a more solid tune. Then hopefully that will address my cooling issues some more.


I am a little relieved that with your 180 thermostat you car will get around 203.

Bubbajones_ya

Just an update,

I did some night driving after getting my new wires and looms in and the car stayed cool the whole time. My gauge only got to 200 for about a second, otherwise stayed around 196, which the EBL computer was reading barely above 180 most of the time.

I did hook up the overflow tank so maybe that had some play in it? However, it isn't too warm out here now, maybe only low 80s, and I know ambient temps have played a huge role in how hot my car has gotten before.

I think one thing I'm going to do to combat ambient temps is make the hood louvers I'm adding functional.

My camaro is an RS, and I already painted my car/hood which looks pretty good, but there were a few dents that I missed that kinda bothered me. I got a really good deal for an IROC hood (20 bucks! without louvers though) that had way less dents in it and was in overall very good shape, so I painted that one too and am using it now.

I did purchased some used louvers that need paint, but figured, I need to reclear my hood now (becasue bugs and dust messed the clear coat) so I may as well modify the hood and reclear it, then put on the functional louvers and see how well the lowers the temps.

redneckjoe

try drilling 3, 1/8" holes around the thermostat. that will allow a small amount of coolant circulation all the time & may aid in getting any air bled.

water-wetter is a good product. i use it & it works.
http://www.redlineoil.com/product.aspx?pid=74&pcid=10

ive seen guys put intake gaskets on backwards, but you said you have flow.

i took my lower air-dam off and made my own out of aluminum. its angled forward in the front to scoop air up into the rad. it works for me, but gotta watch out for parking curbs, etc.

maybe you got some crud built up in the block? you could pull the block drains and flush it out real good.

1979z/28

My Primary Fan stopped working on a 1987 Camaro, no power on my Red and Black wire! Any help out there?

SbFormula

The more I think about it, I've seen close to 212DegF (100DegC) on mine while monitoring. Again on hot summer days during afternoon with smog. That was when I use to live in the city.

SbFormula

Steve Mack

iTrader: (5)

Have you checked for leaves and junk collecting in between the condenser and radiator.Alot of stuff can collect between these two.

Bubbajones_ya

Yes, both the condenser and radiator are fairly new. I had the radiator off recently so there is no debris in-between either, along with the fins on both being pretty straight.

Maybe, with my high flow water pump, water is pumped through the radiator too fast so it's not giving it time enough to cool, and/or the tune of the engine is keeping it a little hotter. I'll have to work on tuning my car, it's just something I'm pretty uneducated at so it will take a while.