OK LOOK!! I PUT NEW HEADS,HEADGASKETS,ARP BOLTS MEZERE WATERPUMP ON MY CAR ABOUT A MONTH AGO. I HAVE HAD NOTHING BUT PROBLEMS. MY OVERFLOW FOR MY RADIATOR BLOWS OFF UNDER HIGH RPMS 5K+. I USED THE SNAPON COOLENT TESTER. IT CAME BACK HEADGASKET OK.(CALLED SNAPON MFGR OF PART. ALL GOOD WITH DEXCOOL.) CHANGED THERMOSTAT(DRILLED HOLES) CHANGED RADIATOR CAP. STILL DOES IT (5K+RPM OVERFLOW CAP BLOWES OFF.) THE OTHER DAY I PUT THE STOCK WATERPUMP BACK ON. ALL WAS GOOD. TONIGHT I WAS UNDER HARD ACCELERATION AND IT DID IT AGIAN. I USED GMPP HEAD GASKETS. C

CAN IT BE GETTING BLOW BY THROUGH THE HEAD GASKET??? I AM OPEN TO ANY IDEAS...IF I GOT TO TAKE THE HEADS OFF WHAT KINDA OFF GASKET SHOULD I USE. CAR DID 465RWHP 431RWTQ IS ONE GASKET BETTER THAN ANOTHER.

 

No Ideas!!! I Am Open To Anything

 

What year is the car? What head gaskets did you use? (part #)

 

Its A 99 I Used Gm Gaskets

 

Your Coolant System Is Pressurized, I Don't Know Why Though!!!!!

 

sounds like its loosing compression by the fire ring"part of the headgasket that seals the cylinder".....you have arp bolts id try a re tork never know it may work....

 

Is There A Good Head Gasket That I Should Use??? I Thought The Gm One Where Good

 

NO ****!!!!!

 

I'm thinkin they gave you the wrong head gasket for your 99.