Ok i have an 88 camaro sc with a gm 350 with about 300hp, here are some of the facts i have a 160 thermo 200 fan switch new radiator and water pump. My problem is the car will run too hot and it wont cool down. If i start my car up in the morning even after sitting for like 10 hours it will warm up to 150 degrees in less then 3 minutes of idling, if i drive it basically looks like the thermo isnt even there becasue if i watch the gauge it barely even slows down when it hits 160, the temp just keeps climbing to 200 all in minutes and then the fan goes on and stops it for maybe 10 minutes, it wont cool down it will just stop it then it will continue to climb to 210 somethimes hotter it all depends how long i am driving also if i have the heat on it does almost nothing to cool the car down. I though my fan might be at fault so i disconnected it and the temp went from 200 to 230 in less than a minute. So far ive checked the timing 14* flushed the system air dam is there, water pump is flowing, however i heard i might have gotten the wrong water pump how do i check this?
i think this really might be it i hope, no leaks pressure held fine car is not lean i pulled the plugs and they look good as well as only getting 8mpg i know im not lean. Sorry for the long post but i am getting desprerate, all help is greatly appreciated and all opinion are very helpful. Thanks

 

If you've got a serpentine belt, it should be a reverse flow waterpump IIRC. If the v-belt design, of course it's the opposite. Do you have a brand and part number for that pump?

 

Yes i have a serpintine belt and i asked for the one for my car and i know it should be the reverse flow, im saying maybe its possible he gave me the wrong one, how can i check this?, no i dont have the part number i bought it a while ago and now im trying to eliminate all possibilities and ofcourse the water pump is one of the possibilities. Any more ideas incase its not that? thanks.

 

I believe that small block chevy water pumps will mount to any sbc block, it's just the internal impeller design that differs. Have you tried pressure checking your system as well as the radiator cap? Maybe there's a small leak in your heater core or somewhere else allowing the pressure to escape? Are you certain your thermostat is opening?

 

The thermostat opens and yes ive pressure checked the system and no leaks, keep the ideas coming i definately need them.

 

Come on guys, i need all the suggestions i can get, things that i possibly didnt check or think of. All help is appreciated.

 

Is the system bled??

 

You need to check the temperature guage. A bad connection can give false readings. The temperature rise is so quick it does suggest an electrical short or bad earth.
The car should run at around 220 when moving,, and maybe a bit hotter in traffic.
If you are not loosing coolant the engine may not be overheating.
If you upgraded the engine you need a much bigger radiator. If you put 300 hp through the wheels, you need to put maybe 400 hp in heat through the radiator.

 

RPM WOT L 98: Yes the system is bled.


Andy Bush:
The connections at the temp gauge are good and it is an autometer phantom series gauge so i trust it. It shouldnt run anywhere near 220 lol i have a 160 stat and a 200 fan switch that goes on at 200 and off at 185, did you read my original post? I wish it was 300hp to the wheels but i meant 300hp at the flywheel. Thanks for the help so far and please keep the ideas coming.

 

I know it says you have a new radiator in your original post, but what type of radiator is it? Just a single row stock replacement? It may not be enough. What type of fan setup do you have? I've just put a dual 11" SPAL fan setup on my stock '89 IROC L98, and thought the stock guage may not be accurate, I never hit 220*. Like you I also have a 200/185 fan switch. Have you made sure that your lower hose isn't collapsing? Another idea that I have heard but not done is drilling small holes through the lip of the thermostat. If that still does not solve your problems, I would suspect that water pump is the incorrect one for your car. Maybe they slipped up and gave you a standard rotation one. As a suggestion, Stewart sells an excellent cast iron pump for around $85.

 

It is just a stock replacement modine and i have a single fan. The lower hose isnt collapsing and ive already tried the holes in thermostat thing, it helped but not much at all. Maybe it really is the water pump, i will pull it off tomorow or tuesday and try a different one. If there is anything else i should check please let me know. Thanks.

 

How is that cooling system doing? I'm curious to see what you find.

 

Believe me ill keep you guys updated, when i get home from work im gonna check on a few things and let you know.

 

The engine is designed to run with coolant in excess of 200 F. Section 6B4 of the Chevy workshop manual.

They actually recon that if the car is not loosing any coolant and a high temperature reading happened thy would check for thermostat openning, and if it opened they would work on a faulty engine light.

The engine won't cool much overnight, it is unlikely in warm weather to cool much below 20 - 30 F above the average temperature during being switched off. So it could be starting up at 80 to 100 F engine internal not external temps.

In that case it would hit 150 and get to 200 F in a few miles of traffic.

Seeing how everything else including the fan is indicating no problems it sounds like there is nothing wrong with you engine.

Older engines are about 40% efficient so 60 % goes in heat. So whatever is at the flywheel add the inefficiency. A 300 hp engine is making 750 HP in combined heat and power.

 

i have a 89 formula with a 4++ cubic inch 11.5-1 motor with alum heads 160 stat factory fans and radiator with a hypertec fan switch no cooling probs.car stays 160-70 no matter what i do.. it makes well over 400 hp at the wheels
has no ac though
do you have two fans or one?
it sounds like the wrong pump....

 

Andy Bush:

You have a very good point, my engine temp is most likely at 70degrees or more even after sitting all night so i guess warming up to 150 in about 3 minutes is not that unusual, however it seems too quick to me, i think that it should take 5 minutes maybe a little more. The real problem is that it wont cool down it will just keep climbing even with the fan going. When the thermo opens it will stop climbing for about 30 seconds to a minute but then continue to climb until the fan comes on and the it will stop climbing for a little while anyway.

Tony Walch: I only have a single fan but it is doing its job i am going to order a stewart water pump( ive wanted one for a while anyway) and if that dosent do it its gotta be my radiator cause i have basically ruled everything else out.

Thanks for your help guys. I very much appreciate it, i will be sure to keep you updated.

 

You know this is why they stopped putting normal temperature guages in cars. They look normal but they do not show the actual engine temperature, they just stay constantly at a point left of the middle so it looks OK to the driver. They only move when a real problem occurs.

Also the coolant temperature is not as critical as the head metal temperature, which is what you really need to know. It is easier to measure coolant.

The original design says over 200 F if you run cooler, the pistons stay too small, the gas condenses on the cylinder walls and the pistons eat the cylinders. The exhaust blows by the piston rings as if the engine was worn out, the oil gets contaminated and oxidized too early. On really old engines before hydraulic lifters the valves did not open fully and the rockers would wear out quicker.

The combustion is over cooled and reduces power and efficiency along with the power lost through blow by. Efficiency is a function of the difference between combustion temperatures and the outside air temperature.

You also get chilled spots leading to cracks and engine distortion.

The 400 HP only happens rarely in a street camaro - unlike in a race version - as the engine transitions a point on the rev range going through peak throttle settings. The rest of the time it might only put out 20 hp so it can easly be overcooled if teh radiator is set up for sustain high power. You could have a 600 hp heat capable cooling system working on only 30 HP.

 

Andy Bush:

That is some very useful information. I never knew that having my engine run cooler could have negative effects. I do not want my car to run as hot as stock, but after reading your post i am re-thinking wanting to run at 160-170 degrees. Do you think that a 180 thermo with a fan turn on temp of 210-215 would be a better choice instead of my current combo? What setup do you run? Thanks for the help so far.

 

Make sure your fans are turning the correct way. Don't overlook something stupidly small. It happens.

 

I think the problem such as it is, is the electric fan can only come on after the coolant gets hot. But really it needs to come on before extra cooling is needed, like after high speed driving and coming into a traffic jam on a hot day.

Once the coolant temperature is up and the fans are on, but the car is not moving, there is no way for the cooling system to quickly remove all the heat still in the engine. Hence climbing temperatures.

It doesn't help that the air intake is at the top of the engine sucking in really hot air, and that the Camaro has to suck air up and through the radiator because of the enclosed nose. Then the hot air hangs around the engine and partially recirculates through the fan.

Working on the engine with the hood open, you can feel all the heat escaping which would otherwise be trying to find a way out of the engine bay.

That heat makes the drivers cab hotter which increases the A/C load and heats up the condensor which is in front of the radiator. The whole design is asking for an overload in traffic.

Personally I would try to set the fans to come on slightly sooner, but fit the normal thermostat. I prefer the mechanical fan to make life easier.

On some cars you can fit another fan and have it on a manual switch, you can put on if you think you are going to need it.

 

Update:

Ive installed the stewart stage one water pump along with one of thier 180 degree modified thermostats, it now takes slightly longer to reach the temp it was but i still have the same exact problem, last night it got up to almost 230 and it was still climbing, the fan was on and so was the heat. and i was moving at about 35-45mph. What could be causing this? Im getting desperate now, please help me! Im about to buy a new radiator, i dont have much money but i am willing to spend what i have to fix this problem, once again all help is greatly appreciated. Off topic but on top of this problem somehow i managed to melt a starter wire with my headers and now my car is out of commision in front of my house, I have no luck what so ever. Keep the thoughts coming guys. Thanks

 

CAMAROsc350,
Could you possibly post any pictures?
I thought something might become obvious if someone here sees it.

Could you tell me if you have a stock or a cowl hood and if the plastic piece that blocks air from coming around the hood latch area is there?
Also what type of distributor do you have and what are your timing settings for initial and with&without vacuum advance.
Thanks,

 

305sbc:

Thanks for the quick reply, i have a stock 91 z28 hood, what exactly would you like me to take a picture of? I can do that no problem, Im not sure which plastic piece your talking about, is it the piece that goes from the back of the radiator to the front of the car if so yeah i have that but its a different one that stock it is also from a 91z but i doubt that matters. I have a gm performance parts hei with vac advance. Initial timing is at 13* which was reccommended for me to use by who i bought my engine from, and ive never checked advance with or without vac connected.

 

Yes that's the right plastic piece. It helps by keeping air from going over the top of the radiator. Cowl hoods can also allow air to go over the radiator but you don't have that.

Is your A/C condenser blocked? fins all bent? or is there trash lodged between it and the radiator?

Does your fan seem like it moves a lot of air through the radiator or does it spin rather slow?

 

The a/c condensor looks good no garbage blocking it or between the radiator however i might take it out anyway just to see, the fan definately seems that it is doing its job ,its spinning pretty fast. What else do you think it could be?

 

I don't know, just trying to narrow things down.

What mix of coolant do you use? or is it just water?
Have you tried running without the tstat & running straight water?

I'm wondering if you have an active tstat bypass on your engine. The pics might help determine that.. as in how the heater hoses are run and if there's an extra loop (hose) from the intake water passage to the water pump.

If you remove your rad cap and look down the hole with the engine running and you see coolant moving like it should then it doesn't sound like a pumping problem.
If it's not a pumping problem (coolant flow), then that leaves only an airflow problem through the radiator.

 

I had exactly the same problem. The only fix was the Be-Cool radiator. I tried EVERYTHING ELSE. That radiator and a two-fan factory set-up cured the problem. (I had to add the two-fan setup. My car originally came with one fan.)

 

What about the plastic piece that closes off the bottom?

 

305sbc:

I run about 60 percent water the rest a/f. I nerer yanked the t-stat or ran straight water, to me thats kind of band aiding the problem. Ill take some pics tomorrow and get them to you. There is plenty of flow through the radiator especially with this water pump.

Barry85Iroc:

You say you had the same exact problem, could you please explain what your car used to do and what does it do now? what temp does it usually stay at now and how do you have your fans set?what temp on what temp off? How much did your set up cost? And lastly what piece of plastic are you talking about?

Thanks

 

There is a piece of plastic that goes under the radiator between the front and the radiator. (IT attaches in the front where the spoiler attaches and in the rear where the fans mount.) My car did not come with one, but I just bought one on E-bay for 20, I'll let you know if it works.
My car would run hot ALL THE TIME, unless I ran a 195 thermostat. I upgraded to a three-core brass and copper.....no help. I added a pusher fan in the front.........no help, I left the pusher fan in, and went to a 2-fan set-up(factory)....no help. By the way, this was all with the stock motor. In TX, if i was caught in stop-and-go traffic, I've seen the factory guage PEGGED at 260, but it never boiled over or overheated. I have added the Be-Cool rad,and the new motor, 200+ horsepower, removed the pusher fan, run a 180 stat, and when it's 105 with 90% humidity, no A/C running, the MANIFOLD temp doesn't get over190. The head temp stays at 180 or less(factory guage. It's hard to tell) With A/C on now, manifold temp goes to 210, head temp goes up to 190. Oh, both fans come on at 170. And they never shut off. I need to fix that . I'm waiting on a B.O. part from Summit to do that. But the car now runs too cold. It seems to run best when the manifold temp( I have an Auto-Meter temp guage hooked to the manifold) is about 200. Feel free to e-mail me if this isn't enough info. You can find thoses 2-fan set-ups used on ebay all the time for 70-100 bucks complete. I rewired them and put in separate relays and soon separate sensors for each fan. Hope this helps.

 

Okay a pic of under the hood and under the nose where the air dam is might help.

I never run a tstat or antifreeze in the summer and I run around 160* unless I'm stuck in traffic, then I have to use a single electric fan.
Right before winter I put in a 195* tstat and antifreeze & hook my heater hoses back up.
I always keep my bypass blocked off.

 

Barry85Iroc:

I know that piece of plastic your talking about, i dont have it anymore i forgot completely all about it. I was in an accident a few months ago and i needed an new bumper and hood, when they yanked it they never put it back on. Im going to get one right away. I dont know if its that important, but i didnt know the air dam was important either at one time. All i know is that before the accident crusing at about 55-60 in about 60 degree weather with all stock cooling compnents and a regular 180 stat the car would not go past 185 even after 14 exits on my way to school and this was also with a strong coolant mix. please let me know what the results are when you install it i am very interested.

305sbc:

I dont know where my digicam is so i cant get a picture, i have a few other ideas as well, im extending the ducts behind my foglights into my original ducts for the radiator, it might do nothing but its worth a try, im also gonna pull some morea a/f out and add water and maybe a bottle of water wetter, currently my car is dead so i gotta fix that first then back to the cooling problem.

Thanks for the replies so far guys i really appreciate it, keep them coming.

 

You know what man? After going through all of what you have, I'd seriously be looking at a new Griffin or Be-Cool radiator. The Griffin 31" x 19" circle track radiator fits in nicely. When it comes time that my stock unit bites the dust I'll be getting that one too.

I've already got a dual 11" SPAL fan setup. These things are really great. So far they've done an excellent job of cooling the engine. I'll be moving to Las Vegas this week and I'm interested to see how they will do in the desert heat.

 

I have the same problem, my motor has around 300 crank hp, I'm using the stock 305 radiator, 180 tstat, and an aftermarket electric fan. I've replaced the original fan, had 2 different water pumps, switched intake manifolds(the first one I had was wrong for my center bolt heads), and flushed my cooling system. After all of that my car still hits 220 while driving around town, and on longer drives ittl get up to 260. It's really confusing and I need to know the answer! Haha I'm about to spend my next paycheck on a radiator and not eat for two weeks.

 

Do the engine see overheated? because you culd have a false rerading from the thermostat I have the same setup as you and my car runs grate. try checking the sending unit for the gage that may be giving false readding.

 

The gauge is accurate surprisingly so, I can see when the tstat opens, it brings the temps down then goes right back up, I just bought a radiator so well see

 

How many cores does the current radiator have? I have a 3core in my car with the 305 and I can't get it to 200 if I'm moving.

 

It's gotta be 1 or2

 

Pop the cap off and see. If it's just a 2core you'll probably need to upgrade to a 3 or 4 core.