Brundle

Well, I have had this car for a coupla weeks now and the temp on my gauge always seemed to read a bit higher - it sat up half way when driving steadily all the time, but seemed to be fine otherwise. Where as my 96 Z28 always stayed a quarter of the way up when driving steadily and half way up in stop and go traffic.

Yesterday on the highway, I noticed the guage starting shooting up and quickly got off right before I redlined the temp guage. It appears the head gaskets r fine - checked the oil dipstick and no signs of coolant (thank god).
But I was loosing coolant from the overflow, it was boiling out over. Now its obvious it needs to be flushed. But I'm wondering if there is anything else that could contribute to this?

I've heard possibly the rad cap might need replacing? So I'll probably get a new one and a thermostat too for good measure when I have it flushed. Any other suggestions??

Also, since mine is a '95 Z28, it has the green coolant in it (i believe they didnt start putting in the dexcool till 96). But what I'm wondering is if it matters if I put the dexcool in instead after I have it flushed? Regardless of what peoples personal preference is on coolant, I just wanna make sure its fine to do this. I can't see it harming anything.

TIA,
Ryan

Evilfrog

Raidator Cap. If its old it doesn't have pressure.(which will raise tempature) and it will allow coolant to flow to the overflow at lower tempatures(allowing more coolant in the overflow which will cuz it to overflow from the overflow) This will raise your overall tempature because it lowers the amount of total coolant in the system.

FastZinTennessee

Pressure test cooling system and check efficiency of the radiator. You'll need to rent a pressure tester, or have a shop do it. To check the efficiency of the radiator you'll need to test the temperature differential between the top hose and the bottom hose. This will tell you if the radiator is doing it's job or not. I suspect that you have a clogged radiator. Keep an eye on the coolant level and oil, I had a situation similar to yours, and it took about two months for the headgasket to let go after overheating.

TobyZ28

Make sure your waterpump is ok as well. Look for it dripping on your belt, if you noticed your cars been squeeling a tad lately it may be from the coolant dripping on your belt. Boiling over is caused by too high temperatures (duh). But this can either be because of, or any combination of A) Not enough flow (pump bad or thermostat bad) B) Not enough antifreeze in mixture, boiling temperature is lower than normal. C) Not enough pressure in system, boiling temperature is lower than normal.

So if your going to fix B and C might as well check A too

Brundle

Thanks, for all the responses guys (or girls).
My rad cap will be in tomorrow at the dealership, so in the mean time I'm driving my other car. And I got my hypertech stat in and coolant topped off again. Then I will go get my flush done after I get the cap.

Toby360: It appears as though my pump is ok, no leaks on the belt coming from the weep hole or anything of that sort from what I can see. Cause I had heard how that was usually a sign the pump was going south, but I will keep my eye on that as well. Just in case it does turn out to be that? How much of a pain is it change one of these suckers?

Coupla more questions I wanna ask now too. Well first one is just re-askin one of my questions from my original post and that is: Do you think its ok to run the dex-cool if even it came with the green stuff?

FastZinTennessee: I will be having the system flushed so hopefully if there is any blockage, it will be cleared. When you say your headgasket let go, do u mean from it constantly overheating or just from the one time? Just askin cause I'm kinda worried being as a blown headgasket is my worst fear. Other than that any other labour is fairly easy stuff.

Last question. Sorry to make this post so long. When I ran it yesterday after putting the new stat in (just in my drive way) as soon I shut off the engine, I checked the dip stick for signs of water, and none appeared to to be there and I didnt smell any coolant, however there were a coupla bubbles on the stick (little bigger than pin size). They didnt look how water looks when it separates from oil. But I was just wondering what u guys thought of this. Is it cause the engine had just been running for a while or I am just being paranoid now?

Thanks again,
Ryan

FastZinTennessee

My headgasket let go/blew as a result of overheating it four or five times.

Green coolant is much better than Dexcool in my opinion. If you want the red coolant get some from Toyota, I've heard it's pretty good. Also my buddy runs that in his Supra, and the cooling system in his car is as clean as could be.

Bubbles in the oil? Probably just little air pockets. You'll need to drain it and let it sit in a pan to see if anything separates.