IROCaholic

I am going to be out of town until that sunday night so I wont be able to attend. I doubt I would make it anyway though because my car is still overheating and at a faster pace now that I changed the water pump.

Mr.Wolf

iTrader: (1)

Irocaholic- have you changed the thermostat and is your temp gauge reading climbing real fast to the top when you start it up or do you know for a fact that its overheating. here's the thread back.

IROCaholic

Yeah, I have checked just about everything and changed the thermostat and tried it without a thermo. The temp just slowly but surely keeps climbing to 240+ after about 20 minutes of driving. I dont know what the heck it is anymore but I am starting to suspect either a cracked head or cylinder.

Mr.Wolf

iTrader: (1)

shouldn't it still be cooling though when it cycles the coolant?

IROCaholic

Im not sure what you mean, but I just have run out of ideas. I have done everything, new thermo, new water pump, I have a 31x19 aluminium radiator in perfect condition. I messed with the timing, checked the fans. It just keeps getting hotter and hotter and I know the temp guage is right because the radiator starts cycling water back into the overflow everytime I turn the car off.

esc

iTrader: (6)

Have you seen any water in the oil or oil in the water?
Are you missing any of the "air deflector" pieces under your car?
Do you have electric fans? 1 or 2 ducted or non-ducted,
or are you using a mechanical fan? Clutch or flex fan?
Have you checked your timing recently?

Mr.Wolf

iTrader: (1)

do you have one of those laser thermometers.

IROCaholic

Deflector is fine, no oil in water or vise versa that I can tell, but I have pretty bad oil leak so that might prevent me seeing it. I have a heavy duty single electric fan with shroud that works fine. And I havent checked the timing, but I tweaked it a little when I first got the car running and it was doing the same thing then. Since I have the oil leak I might just go ahead and pull the motor and slap a 383 in there. My new job is paying me pretty well and I deserve a reward for all my hard work.

esc

iTrader: (6)

Cant go wrong with a bigger motor...except it may be harder to cool.

I could never keep my car cool with any combination of electric fans. I ended up going back to a flex fan after several tries.

Anyway, couldn't hurt to check the timing. Is it overheating while sitting, driving slow and/or driving fast(freeway)?

ZONES89RS

iTrader: (2)

My 383 never over heated, i have the sock radiator, stock fan and a pusher fan, thats it.

IROCaholic

It will overheat when sitting or driving, but it heats up alot fast while driving. Also I realize that sometimes bigger motors are harder to keep cool. However when I first built this motor I had cooling problems with the stock stuff so I bought the 31x19 griffin and a high cfm fan and it stayed cooler than any motor I had ever run. It wasnt until I stored it for two years and brought it back to life that I started having overheating problems again with the same equipment. I will check the timing when I get back in town Monday.

FNFAL308

iTrader: (1)

May not be your problem but I had overheating problems due to the temp/fan switch on the side of the motor wasn't turning the electric fan on til it got to about 230 or 240. This car had sat up for about a year when this happened.

I got a universal fan temp switch form autozone. I stuck the temp bulb next to the radiator tank between two fins and then adjusted the thermostat to turn the rad fan on at about 195.

Been working like factory now for two years. You shouldn't need a fan at about 40 mph+, but not much air goes through the front. ANd city driving is so much stop and go that you can't count on the speed.

IROCaholic

Okay, still nowhere with this issue. I worked on it all day saturday and I got nothing. I went ahead and replaced the water pump just hoping it would be the problem but it seems to actually overheat faster now. The temp is literally climbing with the rpms, the harder I get on it the faster the temp climbs. I can start the car and let is idle for 30 mins and it wont overheat but as soon as I start driving down the road the temp starts climbing, and no its not the air dam. I changed the timeing and tuned the carb over just because. Its weird because the car is literally running perfect and its just overheating for some reason.

FNFAL308

iTrader: (1)

How much is it bored over?

Are the fans coming on at about 195 deg?

Have you ever used radiator stop leak?

Do you know what the pressure is running in the radiator? If there is a crack and exhaust is going in the water the pressure should build. You can run the engine without the radiator cap and watch for exhaust to come out. You should be able to tell especially while it is still cold as steam won't be coming out yet.

Oil/water mix is not always a good way to tell as you may have exhaust/water mix.

When you rebuilt it did you get the block cleaned? May have junk in the bottom of the block around the cylinders. It'd have to be a lot though. Not likely to be the problem.

ZONES89RS

iTrader: (2)

You do have a stat right?

esc

iTrader: (6)

OK, I'm grasping at straws now...

The fact that nothing else changed...but the problem suddenly developed after sittting for 2 yours makes me wonder about some kind of corosion plugging up the radiator or something else...or maybe a partially stuck thermostat.

I have seen coolent turn in to jelly and plug up passages...but that was on a car that sat for 10+ years. A good flush with the water hose sealed in to the lower radiator hose and the thermostat housing removed flushed most of it out.

If you don't have a thermostat, put one in it. If you do have one...try runing without it for a little while...couldn't hurt.

IROCaholic

I just took the thermostat out to see what that would do and it is doing the same thing. Also with the huge radiator I have I dont think I need a stat anyway. Would a compression test tell me if I have a crack? FNFAL, what exactly should I be looking for when I take the cap of and run it? One thing I did notice is that the coolant is not rushing through the radiator as fast as usual.

1bad91Z

iTrader: (1)

Possible head gasket leakage ??? Warped heads from being overheated??

IROCaholic

Its possible, but I dont see any signs of either of those. The car runs perfect and all my fluids are fine. I am going to do a compression check soon and maybe try a few more things, but if it isnt fixed soon I am going to be looking to build a new motor. The problem is that I dont have time to build it or install it.

FNFAL308

iTrader: (1)

If you take the cap off and run it while it is cold you could plug off the over flow and place your hand over the cap hole. Feel for pressure build up. It would be pretty quick if this is your problem as it would have to be a bad crack to cause this much problem. But let it get hot also as the heat may expand the crack.

Pops caddy had two warped heads and there was a LOT of exhaust coming out of the radiator. If your radiator smells like exhaust then you have a crack.

Pressure testing the cylinders should be done with air pressure while checking the pressure in the coolant system to see if the cylinder is cracked or the head or head gasket. If putting pressure on the cylinder causes pressure to rise in the coolant then you have a leak. The cylinders will not hold pressure as it will be escaping around the rings, so if you see the air pressure dropping it doesn't mean anything. It is the raise in pressure in the coolant that will tell.

Don't bother with the typical test where you are just checking the compression - not what you are looking for. This will tell you if you have a burnt valve or ring problems though.

Keep in mind when you pressurize the cylinder the engine may turn a little as the piston goes to the bottom of the stroke.

Oh, this may sound simple, but your lower radiator hose should have a wire in it to keep it from collapsing. If it sat for a long time it is possible that the wire rusted away and the suction hose is collapsing. This will stop the water flow.

A properly operating thermostat will only help the engine warm up to operating temp. It will not help it stay cool. Meaning, if you leave it out, you will run cooler (to cold) if all else in the cooling system is working properly.

If you drop your thermostat in BOILING water it should open completely. If not then you need another. Even new ones are bad sometimes. Get a brass thermostat if you can.

There is some additive to add to your anti-freeze that helps to cool the engine. Get it at NAPA.

Wheel Spin

Cooling system pressure test is free and easy. Pick up a loaner at most parts stores, maybe a $15 deposit or so. Just don't pump up too much, else may blow the seal on the water pump...

Otherwise, sounds like a collapsing lower rad hose. Many have a metal spiral winding inside to stop it from collapsing, but these do corrode and fall to bits. Collapsed hose = no flow.

Heh, FNFAL beat me to it....

To add to it though, it's a belt driven water pump. More RPM (driving), means a faster turning pump, trying to move more water, which will collapse the hose even more as suction is increased. Take the rad cap off and squeeze the hose. You should not have much play in it all.

FNFAL308

iTrader: (1)

I didn't think about that cooling system pressure tester. I usually use the compression tester hose to an air compressor. I need to get one of those as it tests all of the cooling system.

IROCaholic

Thanks guys, I have checked the lower rad hose, but I will do it again or just replacec it and then do the pressure check.

dirtywhiteZ28

It may be time for a new radiator cap. If its only a couple of years old I wouldn't think so but, when the cap fails to maintane proper pressure then the cooling system won't do its job. Take a good hard look at that gasket on the cap. A new cap is too cheap to not consider if the old one even looks slightly questionable. The cap is designed to allow a certain amount of pressure build, this keeps the thermal capacity of the cooling system at its peek performing level. If the cap has a small leak it drops the effective operating range of the system dramatically, thus lowering the point at which it loses control and spikes over to the boiling point. Higher RPM's increase the internal pressure of the cooling system, possibly beyond what the cap is able to contain when its sitting at idle in the driveway.

IROCaholic

The cap is great shape, but I will swap it for the one on my truck to see if theres a difference. Thanks for all the input guys.

Mr.Wolf

iTrader: (1)

how bout an update on your overheating situation.

IROCaholic

I havent had a chance to try anything new, I have been too busy. I probably wont be able to touch the car for two weeks or so.