Yesterday I hit the fiero meeting and when I arrived the thing was at 220 it will run cool for a long time but after a long period of driving it starts the heat up to 220 to 230.

Today I was looking at the radiator caps and the one that was on it was vented the stupid lady refured me to this cap... So today I run out and buy a non vented cap and cleaned out the overflow canister (very dirty and plugged up) I havent tested it with this new cap yet (because it takes a long time for it to heat up to 220) And im hoping that will do the trick.

Also what kind of pellets do I get for the caddy motor... The book says I need them and I really hate putting those pellets in the coolant system because there terrible to when it starts clogging things up and we all know the fiero can use all the free flowing coolant help it can get.

And yes I checked the oil to look for anything nasty my oil is crystal clean and the block has been pressure tested with no leaks found.

[This message has been edited by 86fieroEarl (edited 05-07-2004).]

Are you referring to the Bars Leaks brand sealer and conditioner pellets. They work alright but will clog the radiator passages eventually. Why do you want to use them? Do you have a pin hole leak somewhere? You might be better off trying some of the putty radiator sealers that go over the leak, this way you don't have to worry about that stuff in your cooling system. Also, if you are having overheating problems, make sure to check your coolant tubes for kinks and dents.

[This message has been edited by avengador1 (edited 05-07-2004).]

naw no leaks the caddy haynes manuel said I had to use some type of special coolant sealant I guess it helps against the block of corrosion or something... The problem is dont convenenal antifreez help with corrosion

The pellets are reccomended by cadillac to help neutralize the chemical reaction between the liners and the block to retard corrosion also on your heating problem can be caused by a lot of things so I will try to give you an idea of things to check.

Thermostat stuck or slow to open.
Radiator
Hoses collapse at high rpm
Coolant pipes damaged check them .
Timing off
Radiator fan
try those you should be able to zero in on it good luck.

If it overheats only when driving, make sure there is an air dam on the front and that the side flaps that direct the air through the radiator are all there. The fan does not run at highway speeds, you need to force the air through the radiator. You should have a vented cap on the front. The rear cap should be sealed.

I have never used the GM coolant pellets in any 4.9. If GM put them in there when it was new and the engine has never been apart, there's no need to seal it again. I don't even use the pellets on a freshly built 4.9. I've seen the stuff built up so deep that it prevents proper circulation of the coolant around the liners. If it doesn't leak, I'm not putting it in. I don't think the coolant needs any additives to prevent reactions between dissimilar metals, modern coolant should already have everything it needs.

quote Originally posted by rockcrawl: If it overheats only when driving, make sure there is an air dam on the front and.

I did not read all the post except the title, Ours did this too, we fixed it with a frt radiator air dam, we did not have one. Also at the same time we power washed the radiator to clean it.

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