I had a serious overheting problem so I changed the T-stat, diden't do anything. Removed the T-stat still over heated. Then I blew the Water Pump seals from over heating so I changed that.

Now it was still over heating and looseing coolent. So I got a rad flush, new lower rad hose etc. Still over heats.

What happens is when I fill the car up with coolent and water it drives fine and holds temp, fan comes on. Then when I go on the highway or boost it starts to leak the coolent out the overflow and it goes everywhere, all over my engine bay (I have a FMIC with a relocated over flow, its in front of my battery).

Then once it starts doing that the fan won't run anymore and it overheats and leaks coolent again. I'm pretty sure its just coming from my overflow b/c it spits it out like crazy, and nothing leaks when I first fill it up or don't boost.

I don't think its a Headgasket becasue I'm boosting fine and the Vacume is OK.

Any idea on what to do?

Its your headgasket, compression check is the first step in diagnosis.

Just had the exact same thing happen to me Sean. It is your head gasket. If your luckey you have not warped your head like I did. You might want to take it in and have it checked just to be sure. Let me know if you have anymore questions. Mine should be back on the road by mide week!!

I will do another compression check but I did one right after changeing the timing belt and it was in spec.

I'll try again, but like I said I have good power and still build boost. Also no coolent in oil.

But right now I won't over look anything so I'll check it again.

Also once it starts over heating the fan won't come on anymore, like it comes on all the time untill it starts to over heat... conviently when I need it most. LOL

I had this problem and it was the seal on the preassure cap.

Compression check won't always show a bad HG.

Fill it with coolant, go for a drive. Build boost for a bit. If your coolant overflow is full, it's your headgasket.

By the sounds of it, though, you've pretty much done the above.

When you say it is "losing coolant" is there a leak, or is it just disappearing? If there's no visible leak, you're burning it.

Rad cap!
If not, headgasket.

Yeh I have a new Rad cap so It's gotta be the headgasket. Some people say its the rad but theres no reason the rad should work sometimes and then just get plugged up, woulden't make any sence.

Sean, change the top rad hose just to be safe.like I said my old/weak one would suck closed pushing the coolant back into the overflow
splilling coolant everywhere and in turn causing the car to overheat.

Sean,
As others have said, it's most likely the HG. I had the same problem and used a leakdown test to pinpoint the culprit cylinder. The Tech Info section will give you the details on the leakdown test.
I'd also check out the fan temp switch to make sure it's not malfunctioning. Mine also went caput which I believe led to the overheating/HG probs.

JT

im going to borrow a rad and the top rad hose from a friend of mine and I'll let you guy know what happens. I'm sure its the Headgasket but I'm going to try the rad just to be safe.

Head gasket dude.
The same happened to me, It was soo bad cause it happened to me on the highway and one of my rad hoses had a huge hole from the compresion that went into it. Also one of the cylyinders had a lot of water in it