M1tch

Since my new motor installation it has always ran at 160-175. My cooling system is actually over efficient, it will drop down to 130 after the thermostat opens in cold weather. I recently had a problem with my dual core jegs radiator, it would randomly **** coolant out so i replaced it. I also changed the thermostat, and after racing my buddy my fuel pump went out so i replaced that also. my motor will go from 160-210+ after 20 minutes of driving. and EVERY TIME it has overheated the radiator would be cool to touch, maybe 50-80 degrees. So that triggers to me that it could be 3 things.

- thermostat
- water pump
- air in system

I've replaced the t stat, bled the air out of the system, and when i did bleed the air out you can see the water pump working fine, i have a stewart stage 2 pump so it works great.

What other possibilities could it be? could the water pump be working too fast for my rad? Could the water pump randomly quit pumping? Could i have a small head gasket leak? I have no smoke and no coolant in the oil and nothing soupy in the valve covers or pcv valve.

Please guys help me out.. its frustrating

Note: I also noticed some steam coming out of the overflow.

Slick89RS

iTrader: (1)

It sounds like a possible head gasket.

Can you get your hands on a block tester?

It's a simple device that checks for exhaust present in the cooling system.


Another question, you wouldn't possibly be using steel shim head gaskets

JTNKTZ

iTrader: (10)

If you don't go to Midas. They do it for free. Just hope to god that that ***** pumper looking thing doesn't turn green like mine did.

84 z28

Almost sounds like something is blocked and the coolant cant flow. I would take the thermostat out and see if you still have the same problem. Other than that the only other thing I can think of is your radiator hose collapsing and coolant not getting to the radiator.

M1tch

My mechanic said the water pump could be going out also. But i dont see how its possible if it pumps at an idle etc. Another guy told me to unscrew the bolt on my intake to get the air out since its the highest part of the cooling system. i originally tried running it without the cap on to get air out but he said it doesnt work that good.

I wonder if it is my water pump hose to the radiator.. i was told that if it was a head gasket it would overheat fasttt so any more suggestions would really help. I'm going to take the thermostat out and maybe buy a braided water pump hose and get the air out.. see if that works.

M1tch

Update

Today i started her up and i let it run for a while, letting it climb to 160. The top of the radiator was hott where the cap is and the other side of it was cold. What does that mean?

Slick89RS

iTrader: (1)

The side with the cap should have the lower hose connected to it.

I'm wondering if your water pump is the correct flow.

Are you running a serpentine belt or v-belt?

If it is serpentine does it run off the back side (smooth side) of the belt?

M1tch

Update 12/29/08

I borrowed a pressure tester at the local O'Reillys and I found the problem. I watched the guage go from 7-22 psi and it was on its own, pumping compression somewhere inside the cooling system. The weird thing is that I borrowed another tool which checks for combustion gases inside the cooling system, and the solution never went from blue to yellow. So what are my chances at this point? Gasket, block, heads? The exhaust is still not smoking and my oil is fine. I'm praying its not the block :-(. I also noticed that when i would rev from 2500-idle it would almost stall sometimes.
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I'm running a serpentine system, and the water pump is running off the smooth side, with the rough side showing

Stekman

I would hook up a compression tester to all 8. See if any of the cyl's are running less than the others.

Slick89RS

iTrader: (1)

When you check the compression, checked the spark plugs for any signs of discoloration that may also be a clue to which cylinder is the culprit

How long did it take to go up to 22psi in the cooling system?
If it's happening quickly the radiator should push coolant out the filler neck

On the head gasket tester you borrowed...I'm wondering if the cylinder in question is missing (eg fouled spark plug) That means it wouldn't show up on the tester because it's looking for a reaction from exhaust gasses not air fuel mixture. (Beside the fact that pushing air / fuel through the cooling system most of the fuel would be pulled out of the mixture by the coolant)

If it is missing it could also be the reason why the motor is almost stalling.

M1tch

After talking to my girlfriends dad which is a self taught mechanic (built a 78 kenworth from the ground up, and a 65 mustang) he said the way to do the test is to fill the radiator up to 16-18 psi while the motor is sitting and cold and to wait a few hours and come back. he said if you lose any psi that means there is a leak somewhere.

So i did that and found that i have no leak at all. He said he would buy a remanu water pump from auto zone and try that out. should i go ahead and do this or does the pressure increase while its running mean anything?

Slick89RS

iTrader: (1)

That does work when dealing with cooling system leak problems. Sometimes I've seen the system will hold pressure and not leak internally but as soon as you get combustion pressures or just cranking pressures then is when it leaks.

example: cooling system pressure = 18psi or static compression = 180

Most of the time if a head gasket is leaking during combustion it'll burn out the gasket where the leak is located. In that case the test he told you to do would work very well.

If you have a head gasket that's holding cooling system pressure but not combustion pressure that could be the problem.

As for the water pump (like I was getting at in a previous post) is the pump you have installed a reverse flow? If you are in fact running off the back side of the serpentine belt it needs to be reverse flow.

That could be why the radiator gets so hot on the lower hose side. (Its trying to circulate backwards in a very poor fashion)

M1tch

Update 1/22/09

Put a stock camaro 350 water pump on it. I drove it around for forty minutes and had no problems until i pulled it into the drive. I revved it up once and the same old happened. Started heating up and i shut her off. I saw a white texture on the very top of the overflow but it wasnt that thick. I occasionally hear a hissing sound when im driving it. I was driving it hard on the street too, shifting at 3000 because my tv cable pressure is off. Did a few burnouts and everything.. Is the whitish clear texture 100% oil? i dont know what else to try.. im hoping its a small air bubble or a intake gasket leak. It almosts stalls sometimes when its colder and u let off the gas so im guessing its a leak somewhere..

hachiroku_rs

im just going to take a shot in the dark, you said the radiator stays cool, is the block cool too or is it boiling hot, cause if the block is cool also, it just might be the indash temp sensor. also, if its a whitish liquid, it might be contaminated with oil, if you have coolant w/water, water reacts to oils when they heat up, causing it to form a white liquid,when was the last time you did a radiator flush.