87wagon

I just drove on the highway and it heated up to about 220 . It is only in the low 80's here. It quickly recovered to 185 once I quit driving. The only thing that I did not fix or change out is the water pump and radiator cap. From what I been told that is still too hot or is that normal ?

MDchanic

220° is too high.

And though it is reasonable to change the water pump, my money is still on the radiator, or possibly heavy rust accumulation inside the block.

A newer car's temperature wouldn't go up under those conditions, there is no reason why yours should.

- Eric

gregvm

Sounds to me like an ignition timing issue. Did you check to see if your timing advances with rpm?(via timing light and revving engine) or check initial timing? Check to make sure the cent. weights are free and springs aren't tired/broken. Do your exhaust manifolds seem to get EXCEPTIONALLY hot?(that's a sign of retarded timing) If the shroud and all the air dams are in place, I can't see an air-flow problem. What rpm does it cruise at on the hwy? Water pump flow should be visible with t-stat open, cap off, nice steady stream of coolant thru the tubes.
Does this have a/c? Are the condenser cooling fins flattened to restrict air flow to radiator?(check both sides)
just some ideas...

does this have CCC?

87wagon

Timing is good 20 deg. When I throttled it I saw the advance. It starts to really heat up under accleration at highway speeds- passing gear. Slow to recover when driving. Cools off quick when stopped. How to clean rust out of block? The rpm at 75 mph is pretty low. No tack. Od works.

gregvm

Ok, let's try lean mixture....any vacuum leaks(egr valve, pcv,carb gasket etc?) Put a vac gauge on it, that'll give you an idea of engine condition anyway. pull a couple spark plugs.....what do they look like?

87wagon

Every time I pulled the plugs they were tan like they are supposed to be.

It takes about five minutes on the highway at 75 and then it heats up. Air on or off, it does not matter. It heats up more when i acclerate and takes a very long time to cool down while driving. When i pull the rad cap there is a little rust on top. Not very much at all.

rustyroger

Maybe we are telling you something you don't want to hear - you need a new radiator, the one you have can't dissipate heat properly.
It doesn't really matter what else you do, until you have a new core in your radiator you will have overheating issues.

Roger.

87wagon

Yea, everyone was right. I changed the radiator and everything is normal.
Lesson learned - Don't rod out a radiator, it does not help in some cases.

I hear many different mixtures for coolant, should I use distailed water? I heard 50/50, 70/30, 80/20....

I live in the dessert southwest. It will get below freezing here maybe 7 days a year.

Thanks for everyones help.

MDchanic

Distilled water is better, especially if you have hard water, though I never use it myself.

Antifreeze should always be 50/50 - that's the way it's designed to work, and that's the way it will provide the best boilover and freeze protection - it's a matter of simple chemistry.

- Eric

rustyroger

As usual, I concur with Eric.
Antifreeze also has another important function; corrosion and erosion inhibition.
When you have dissimilar metals in an electrolytic solution, and an iron block, aluminium water pump or manifold and coolant is a prime example, with electric current passing through it you get the phenomenon known as electrolytic erosion, essentially aluminium is removed and deposited on iron components. Antifreeze contains inhibitors to stop this process.
Over time the effectiveness of these inhibitors is reduced which is why you should flush and refill your cooling system every few years, and why you need antifreeze even if your car will never see freezing temperatures.

More than once I've had cars that have spent a long time in Spain in the shop after they broke down on the way back the UK. The symptoms were much the same as a blown head gasket, but when I removed the head I found the (aluminium) head had eroded to the point of undermining the head gasket.
They were upset at being told the car needed a new cylinder head, and surprised when I told them it was because it had no antifreeze.

Roger.

ThePackRat

Glad you finally solved the issue.

Figured it had to be the radiator, the cat or a combination thereof.

You should now be enjoying the bonus of some added power ... now that it's running cooler.