hey everyone.

Heres my problem, I have a 93 3.4 v6 and had bad flow in the coolant system. I had alot of dex cool sludge in the radiator so I had the system flushed and replaced thermostat. I tried to use a quick fill tool to refill the system but lost vacuum so I filled it the old fashioned way and did a pressure test. The system held pressure and I can't find a leak. Does anyone know where I may be pulling in air from that wouldn't leak under pressure?

 

are you sure you purged the system properly? If not you could "lose" water for days. How did you purge the system?

Massey

 

Tried to use the quick fill but the vacuum wouldn't hold. My father finished the job for me so I'm not 100% on how. The main problem Im having is that the dexcool keeps sludging up. I've had a few people tell me my head gasket is getting ready to go.

btw I have had the radiator pulled and cleaned, 98% flow and no leaks

 

what do you mean by the quick fill? I do not know what you are talking about? You fill the radiator and let the engine run while the cap is off. Once the T-sat opens it will let the air out of the top of the block and the coolant in the rad will lower. Refil and allow this cycle to happen a couple more times until operating temp is stable. and coolant level no longer overflows or reciedes. Then top off the rad and overflow and call it good.

If the DexCool keeps mudding up you may want to think about using an all makes all models coolant like Prestone.

Massey

 

quick fill is screwed on the radiator and you attach an air hose to pull out all of the air and remaining antifreeze to create a vacuum, then attach a fill line and stick the end into your coolant jug and release the vacuum and it fills up the system. it works really well as long as you can hold vacuum.

 

Sounds like a method of filling a sealed system. This is not a sealed system so why not try a more conventual method.

Massey

 

The coolant won't just keep sludging up. You still have slufge in your system! You need to take the hoses off and back-flush the system. Stick a good pressure garden hose in the hose and let it go until you see clean water come out the other end. Loosen the lower rad hose and upper rad hose and the thermostat hose. Afterwards, use the AC Delco sealant tabs. You'll need to crush 2 of them up and put them in the rad. Don't use stop-leak or other types of stop leak.

Make sure you get all the air out of the system when you fill it back up. Start the car and wait until the thermostat opens. Let the car cool down and fill it up. The rad will be almost empty. Then start the car with the rad cap off and watch for bubbles. When it starts to get close to the top turn off the car and put the cap back on.

 

^^^ agree with the guys, fill it the conventional way. on a older 3.4 i dont think you want to be subjecting it to excessive amounts of vacuum or pressure. it would however be a good idea to do another pressure test just to make sure something has not opened up.

 

Thanks guys, I'll keep you updated