95 Lumina 3.1l heating problems (long)

[procrastinator]

Any ideas on fixing a broken bleed screw on the water pump housing? It is broken slightly below the hole surface. Snapped the head off bleeding it when I realized the shop didn't bleed the system after flushing it 6mo ago.

Second the car is overheating a lot. I'm not noticing any heat either even when it maxes out. Sometimes the radiator hoses are even cool when I pullover to cool off. Have also noticed if I make a quick sharp turn while its starting to overheat the temp will drop back down (sometimes too cool) and eventually the low coolant light comes on.
I'm hoping its a bad water pump or stuck thermostat and want to try fixing it on my own. I REALLY suck at repairs but can't afford a shop right now. Any tips or potential problems for these 2 repairs?

Water pump: 1. remove serpentine belt. 2. drain coolant. 3. remove pulley bolts and pulley (any tricks to this?). 4. remove bleeder screw housing? 5. remove water pump mounting bolts then water pump 6. scrape off/remove old gasket. 7. apply new gasket - no garage, is weather to cool for gasket stuff?. 8. mount and bolt new pump. 9. attach bleeder screw housing - does this need a gasket? 10. attach pulley 11. install serpentine belt. 12. add coolant and bleed system.

Thermostat: looks like a pain. 1. drain coolant 2. remove air cleaner housing and hose thing. 3. remove upper radiator hose. 4. remove thermostat housing then old thermostat. 5 remove old gasket 6. install new thermostat. 7 apply new gasket. 8 reattach thermostat housing. 9. reattach upper radiater hose. 10. reaattach air hose and cleaner housing thing. 11. Add coolant and bleed system. May just have a shop do it if not enough wiggle room after removing air hose thing.
Any help is appreciated.

[Floyd_ODB]

I would think either air locked or thermostat. but I dont know if an air lock condition would cool back down like you said. pretty strange most like a thermostat. howver my brother claims his durango wouldnt blow hot air even though his guage said 200deg. upper hose was hot and lower was cold. he tole me his mechanic said the radiator was almost completly plugged.so much so that the lower hose was cold.
pleas do not get that thing hot any more. you are decreasing the lifespan of thos head/intake gaskets 10 fold. and the heads will etch a groove from the gasket causing them to blow.

[diesel1962]

Sounds like you may have a BHG,(blown head gasket).Also if the shop did not bleed the cooling system properly,your engine would have given you problems along time ago.I have a 95 Monte with the same engine,And it has been giving me the same troubles,I am suspecting a bad head gasket,I will tear into it when weather warms up.(I live in a cold climate,no garage).You can try the thermostat,They have a rubber O ring to seal it,No need for gasket material. I would remove the throttle plate assembley,That will allow better access to thermostat housing bolts.Good Luck!Diesel 1962

[RahX]

on these engines the air is really hard to get out. if you fill it up with teh bleeder open 50% of the time you dont get all the air out of it. if the bleeder is broken off i *think* most of them screw into a bigger screw. if thast the case just loosen the screw the broken screw screws into (lol) and youll be fine. they sell a replacement but it replaces the bigger of the two screws and the screw you broke off. ANYWAY the best way to purge air out of the engine is to make sure its full and make sure the overflow is slightly, maybe 1/4" over the line, overfull. next start and run the engine till its at normal temp. after it gets to normal temp hold the idle at about 1500rpm until it starts getting warmer than it should. now this part is KIND OF tricky to picture but bear with me. when it starts getting warmer than it should rev the engine to about 2200 and let off. let the rpms drop down to 1200 and rev it back up to 2200 and repeat. you should be going 2200V1200^2200V1200^2200etc. this surges the coolant in the engine which also acts to push air past where it normally goes. now if the temp gauge starts dropping hooray. if it doesnt DO NOT let it overheat, shut it down. if you get it to drop, let it drop and warm back up and repeat the process a couple times making sure the overflow doesnt go dry. after you do it 2,3, or 4 times warm it up and shut it down and let it sit and DONT open the system. when it cools down itll suck up even more coolant from the overflow. refill overflow and see if it helps out any. if the process doesnt yield any results, have someone check the headgaskets. also, the lower intake gaskets are prime for leaking coolant. thats a good place to get air from. look on either side of your head. the easiest places to check are on the front head between the exhaust pipe and the intake on the driver side or behind the waterpump on the passenger side. look down the head, where the intake crosses from the head to the block on both sides. if you see quite a bit of coolant loss there it wouldnt be a bad idea to have those replaces. most of the time they just leak out onto the trans/engine. SOMETIMES they leak INTO the intake either into the valley or the cylinders if theyre let go long enough.

[procrastinator]

Bled the system not long after they flushed it. did some research and figured that was the problem and it was fine for a while. These last 3 months have been making weekly long distance trips taking my brother to a specialist. btw the car has abount 98k mile. Going to try notching the top of the screw shaft and see if I can unscrew it. I'm willing it try the thermostat especially if it just needs a rubber gasket. After that I'll think about the water pump. The shop said $330 p/l for pump/thermostat and $1300 for bhg possibly including machining the heads.

[procrastinator]

ok a few pics and some more questions. I ask all these ?s because once I start it may be hard to get free help if things go wrong and I hate not having transportation. Will pick up a water pump and new serpentine belt today (the quickie place said I needed a new belt but I think they just wanted $60). Bought a themostat - it has a built-in rubber gasket but does the thermostat housing need a gasket as well?

its blurry and 3am The broken shaft is slightly below the top of the hex nut.
1) Does the tube need a gasket where it goes into the water pump? 2)Will I need a pulley removal tool for the water pump pulley or should it come off easily once unbolted?


As far as the serpentine belt tensioner. I can see the nut. Do I rotate it toward the rear of the engine until I can remove the belt or does it come off completely?

[JBMark33]

The tube with hoses, the black metel piece with the two heater hoses, does need a small gasket coming into the top of the water pump. I have replaced it before. The water pump has 4 pulley screws, then 5 more inside, then the water pump will come out, take a screwdriver and get all of the old gasket off, then put in the new water pump and gasket, put all screws back together. As for the thermostat, take off air intake plastic boxes with air cleaner. then take off two screws and take off throttle body so that you can reach the thermostat housing easier. The thermostat comes with a rubber gasket that is needed. The housing for the thermostat does not need a gasket, it just tightens on around the thermostat. By the way....using the tire iron helps take tension off the serpentine system when you try to put the belt back on.

[RahX]

there is an o-ring on that pipe going into the waterpump housing. lube it up with some light grease or something and it should be ok. the bolt should come out like normal.

[96Lumina3point1]

Proc,

The front end of the Belt Tensioner is squared-off so you can put something like a Crescent wrench on it. You don't need anything more than that. Just put the wrench on it and lift up. Easy as pie!

~Annah