Just did intake manifold gasket...still losing coolant. Nooooooooooo!

[munly]

Hi. This is my third post in three days. I just did the intake manifold gaskets a few days ago. I've marking the coolant level in the overflow tank while the truck is parked overnight to try and get an indication of leakage. It seems to be dropping slightly after each night. My only hope is that the coolant is moving into the radiator, hoses, etc causing the level to drop in the overflow reservoir. I say this because when I drained the rad (from the lower rad hose) only 7-8 litres drained from the truck and that's all I poured back in to top up the rad. Maybe there was some trapped air in the system that's getting pushed out causing the coolant level to drop. Either that or the gaskets are still leaking...sigh. There is no external leak that I can see and when I mark the coolant level in the overflow reservoir the engine is cold. Anyone got any ideas. Thanks.

 

[Big98z71]

More than likely just air working out, if you can get your hands on a vacuum pump you can pretty much pull all the air out. Have you watched your oil level? If you have a leak on the inside it will of course drain to the oil pan, oil floats on water.

 

[munly]

Yea...I'm hoping its air working its way out...really hoping, pulling that intake is a pain the arse. If I got a vacuum where would I hook it up to pull the air out? Also, I thought the oil and coolant mixed more so than the oil floating on top of the coolant. Thanks.

 

[someotherguy]

Drilling a couple of small (like 3/32") holes in the flat area of the thermostat helps immensely in bleeding air out of the system. I do it on any new thermostat I install. (There are also a few brands with a bleed hole already in them.)

If you suspect something is still leaking, time to rent/borrow a cooling system pressure tester.

Is this a Vortec or TBI engine? Seems like I've heard of at least a couple Vortecs being warped at the intake, and more sensitive to it since all the bolts are essentially outboard in comparison to TBI.

Richard

 

[TylerZ281500]

Drilling a couple of small (like 3/32") holes in the flat area of the thermostat helps immensely in bleeding air out of the system. I do it on any new thermostat I install. (There are also a few brands with a bleed hole already in them.)

If you suspect something is still leaking, time to rent/borrow a cooling system pressure tester.

Is this a Vortec or TBI engine? Seems like I've heard of at least a couple Vortecs being warped at the intake, and more sensitive to it since all the bolts are essentially outboard in comparison to TBI.

Richard

i never thought of that. hmmm. if its losing coolant and not using like was stated and ai bubble or warped intake are you best bet, hopefully its just air in the system, if its burning it you need head gaskets.

 

[munly]

It's a 98 5.7 vortec. I'm really hoping its air working its way out of the system. I'm gonna retorque the intake bolts to 11ft/lbs...do these bolts loosen off during heating/cooling of the motor? Thanks again.

 

[Big98z71]

Someotherguy is correct, it's a cooling system tester, goes on just like a rad cap. I don't run a thermostat in my 98, I bought it with 159,000 ,lies and immediately pulled it out, I live in kansas and pull a lot and use my truck in the winter to feed round bales. Heater works great, will even cook you out. Even then when ever I replace or repair anything dealing with the cooling system it still takes a couple days driving to get all the air out

 

[TylerZ281500]

to bleed the cooling system let the truck run with the cap open, keep filling it when it gets low and itll overflow when its done bleeding.

 

[someotherguy]

^^^ can sometimes take several cycles of the thermostat, helps if you park uphill on a steep driveway/hill or put the front end on ramps/stands, so the radiator neck is the highest point in the cooling system.

Richard

 

[TylerZ281500]

i always turn my heat on too, im told it does nothing but ive never complained about not having instant heat when needed in the winter.