1994 Oldsmobile Cutlass Supreme 3.4 liter Twin Cam Overhead Aluminum Head Engine---- About 120,000 Miles---Engine overheated, have installed new radiator, water pump, thermostat, all hoses are good, see no signs of blown head gasket, no water in engine oil, no signs of water in oil filler cap, no water out the tailpipe, engine still runs good. Bottom radiator hose does not get hot, no heat from heater,(blows cold air). I have been getting eratic readings from the temp. guage. It will idle in the normal range--then shot up to the red zone when driving--then drop to normal.I disconnected bottom radiator hose with the engine running, no water circulated out from water pump housing, then I disconnected the top radiator hose at the thermostat housing, no water being circulated. I can not understand why the water pump would not be pushing water thru. The owners manuel says there is a special cooling system filling process on the engine, it has 2 vents, one on the thermostat housing, and a heater hose pipe, I followed the recommended filling process, no success. It seems to me that the cooling system does not have enough water in it. Maybe that is why the heater blows cold air. My other thought is that the engine has a pocket of air trapped in the system, but I do not understand why the water pump is not pushing water thru the system. I know that these engines have had problems with overheating and head gaskets, but I have not been able to see any signs of a leaking head gasket, however I have not done a block test on the engine. Do you have any suggestions as to what the problem could be, I do not want to pull the cylinder heads unless I am sure there is a headgasket problem.
There seems to be an air pocket or no antifreeze in engine block. Try this method disconnect upper radiator hose and pour water directly into hose down into engine block until it full. when its filled reconnect hose and fill up radiator. as the vehicle warms up open bleeder valve on the thermostat housing and release air from system. open slowly and BE VERY CAREFUL WATER WILL BE HOT, bleed until you get a steady stream opening and cosing valve. However if all of this don't work. You may have a bad pump. Good Luck
when you open bleeder screw on thermostat housing do you get water spraying out?
Hope that you didn't get one with a bad impeller, I've seen that once in my shop. The pulley on the outside turns but if you hold the impeller and turn the pulley it still turns the shaft that was connected to the impeller was defective.
Do a compression test on all cylinders numbers should NOT be more than 10 Psi difference between each other . Good Luck
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Foot pounds (Final torque)
Note:
Torque sequence --------- | 6 2 3 7 | | 5 1 4 8 | --------- Step 1: torque in sequence to 33 Ft/Lbs Step 2: turn an additional 90 degrees Recheck final torque in sequence *** CAUTION ***engine uses Torque To Yield head bolts (TTY) thatpermanently stretch during the initial installation.New head bolts must be used when cylinder head isreplaced or re-installed to obtain proper torque.
Foot pounds (Final torque)
Note:
Torque sequence --------- | 8 4 1 5 | | 7 3 2 6 | front --------- of engine | 6 2 3 7 | | 5 1 4 8 | Step 1: torque to 40 Ft/Lbs --------- Step 2: turn an additional 90 degrees Recheck final torque in sequence *** CAUTION ***engine uses Torque To Yield head bolts (TTY) thatpermanently stretch during the initial installation.New head bolts must be used when cylinder head isreplaced or re-installed to obtain proper torque.
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Thanks for the quick reply, I have already tried your suggestion of disconnecting upper hose and filling engine block with water (not antifreeze) with out any success. I have installed a new water pump (not rebuilt) also with out success.
When I open bleeder valve on therm. housing, I can not get a steady stream of water to come out. I get lots of steam, with a once in a while spit of water. Today I,m going to try adding water to the engine block thru the therm housing again. Also going to try to verify that water pump is turning or not.
Today I tried to add water into the engine block thru the termostat housing again. It took just a small amount. I tested the thermostat in a pot of boiling water to verify that it is opening up, it is. I replaced the serp. belt as it was full of cracks, and was starting to shred, I thought it might be streched and not putting enough pressure on the water pump at speed. Still I have a cold bottom hose. I disconnected the bottom hose with the engine running and there is no water coming from the water pump housing. The radiator is boiling at the filler cap, the heater hoses are cold. No matter how much is try to vent the system at term. housing, I can not get a stream of water, just a few drops, mostly steam. I guess the next step is to pull the new water pump and to see if there is a problem with the impeller. At this point I will try anything. I still do not see any signs of a blown headgasket, no water in the oil,or at the filler cap. I know that the water pump must push the water thru to cool the engine, and right now it is not. Thanks for interest with my problem
Today I pulled the water pump again, Did not see anything wrong with it, but I replaced it any way( they are not exspensive for this model). It did not help. There is still no water being pumped thru the bottom Radiator hose with the engine running. Altho I seen no signs of a blown headgasket, someone told me that the headgasket could be bad, and it is pumping air into the closed cooling system which is not allowing the system to fill with water. I have never seen or heard of this happening, have you? Do you know of anyway to test the headgaskets with out pulling the heads off.
A few days ago I did compression test, and found the problem. No 4 cylinder showed 220 pounds of pressure, comparded to 165 to 175 everywhere else. I knew this was where the problem was. I disconnected the compresstion tester and turned the engine over and got a face full of water. I'm the process of doing the head gaskets now. Not a fun job on this engine. I have the heads ready to come off, but have not taken the timing belt off yet. I have the timing marks together as they are shown in the service manuel, but the cam lobes on the No 1 cyl. do not look like they are in the closed position . About 4 years ago I had a shop put a new timeing belt and they left a few white marks on the cam gears that due not line up. I was wondering If they could have set the timing on another cyl. rather on No 1. Any feed back would be help full.
My daughter has the same car / engine & exactly the same problem. 140,000 miles - Had 2 thermostats put in - and a water pump. The overheating is eratic - can go for days without any issues. Working through a master mechanic who feels it is electrical - he drives it for days with no problems. Also see's no sign of Head gasket failure. A couple days later it all starts again. Shutting it down and letting it cool seems to correct the condition. I don't agree that it's electrical (bad gauge) it does not explain that the heater core continues to blow cold air after 20 minutes of driving while the Engine temp is pegged in the red - and the the check engine soon lite is on along with the fan although they are all likely activated by the same sensor.
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