Leaking thermostat housing

[Larryjb]

I just finished redoing the thermostat housing. I cleaned the thermostat housing and water pump mating surfaces with acetone first. Then I used a thin bead of Permatex water pump and thermostat housing RTV. I place the bead around the mating surface just outside the gasket area. I installed it immediately, but finger tight. An hour later I torqued it down to 132 in-lbs. I was supposed to wait 24 hours before filling the system with coolant, but I could only wait about 9 hours. I'm pretty sure that will do. I'll run it for a day with the pressure cap loose. This way there should be very little seepage past the OEM gasket, and it will have pretty much set anyway.

I'll keep you posted on the rattling tensioner. I'm suspecting this is not due to compressor slugging, but instead due to coolant dripping on the compressor clutch and belt.

 

[Tonyrodz]

I just finished redoing the thermostat housing. I cleaned the thermostat housing and water pump mating surfaces with acetone first. Then I used a thin bead of Permatex water pump and thermostat housing RTV. I place the bead around the mating surface just outside the gasket area. I installed it immediately, but finger tight. An hour later I torqued it down to 132 in-lbs. I was supposed to wait 24 hours before filling the system with coolant, but I could only wait about 9 hours. I'm pretty sure that will do. I'll run it for a day with the pressure cap loose. This way there should be very little seepage past the OEM gasket, and it will have pretty much set anyway.

I'll keep you posted on the rattling tensioner. I'm suspecting this is not due to compressor slugging, but instead due to coolant dripping on the compressor clutch and belt.

Good luck!

 

[Larryjb]

So far, so good. I still have to give the AC belt and pulley a good cleaning, but I'm getting much less tensioner chatter now. It appears as if what I thought was compressor slugging was actually a slipping AC belt causing the tensioner to rattle.

If you hear the telltale signs of slugging, or see evidence of it on the tensioner as I did, do a pressure test of the cooling system and check for leaks around the thermostat housing. I'm wondering if some people have had compressors replaced for no reason.

All in all, I first blamed the aftermarket tensioner for the failure. It may have been perfectly fine, except the slipping belt caused the tensioner to fail. The thermostat housing and waterpump were also aftermarket. Perhaps the waterpump has imperfections or slight warping on the surface preventing a good seal. I may have to replace the waterpump in the future if the same causes leaks between the block and waterpump. Either way, the Permatex waterpump sealant seems to have done the trick for now. I have yet to do a pressure test, but the level has not gone down in the last couple of days now.

Check your thermostat housings!

 

[Larryjb]

I've experience some compressor rattle. It seems worst in the higher temperatures, but that might be expected as the AC gas pressures are higher.

Going on the theory that the coolant leak caused the belt to slip, I removed the ACDelco belt tonight, used a bristle brush and cleaned the compressor pulley and crank pulley with acetone. I installed a Gates belt instead. We'll see if there's any change. If not, I may be looking at a new compressor.

 

[Larryjb]

Still getting the compressor rattle with the new belt. It looks as if it's time for a new compressor according to the TSB http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=125566

 

[Larryjb]

I just came across this:

Look for Viking2121's response. His started locking up when his water pump leaked onto his compressor. That's exactly what's happening to me. Mine was perfect until my thermostat leaked onto it. I will try the WD40 trick and see what happens.

 

[Larryjb]

I just tried the WD40 trick. So far no luck. I did read somewhere from some guy who torn down a compressor that was behaving like mine, and there was internal damage. So, I'm probably going to have to replace the compressor. I figured as much, but I thought it was worth trying.