Erratic oil pressure after belt replacement and waterpump relplacement
11-08-2002, 02:56 PM
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Erratic oil pressure after belt replacement and waterpump relplacement
Greetings everyone,
I've just had the belts replaced and the water pump replaced on my '87 944 and I now have a new problem. The oil pressure is low and becomes very erratic (the needle on the guage jumps up and down a whole lot!) as the rpm's increase. I only drove it home, about a mile, while this was happening. I was concerned the low pressure, and even the occasional appearance of the warning light, would do damage! Could the cause of this be an under torqued crankshaft pulley bolt? I think I read somewhere that the high torque requirement is required because the oil pump drive gear relies on the friction of the torqued up pulley stack on the crank to hold it stationary on the crank. An under torqued bolt will cause the oil pump to slip resulting in very low pressure. Has anyone ever heard of this? If so, this would make sense, since the oil pressure was fine before the replacements. Any information would be helpful, and greatly appreciated.
Thanks,
Kelly
I've just had the belts replaced and the water pump replaced on my '87 944 and I now have a new problem. The oil pressure is low and becomes very erratic (the needle on the guage jumps up and down a whole lot!) as the rpm's increase. I only drove it home, about a mile, while this was happening. I was concerned the low pressure, and even the occasional appearance of the warning light, would do damage! Could the cause of this be an under torqued crankshaft pulley bolt? I think I read somewhere that the high torque requirement is required because the oil pump drive gear relies on the friction of the torqued up pulley stack on the crank to hold it stationary on the crank. An under torqued bolt will cause the oil pump to slip resulting in very low pressure. Has anyone ever heard of this? If so, this would make sense, since the oil pressure was fine before the replacements. Any information would be helpful, and greatly appreciated.
Thanks,
Kelly
11-08-2002, 03:02 PM
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the oil pressure warning light and the gauge are two seperate circuits, so if you have seen both it is unlikely you are suffering from the usual cause of a "fluttering" pressure reading--a bad ground.
i beleive you are correct about the crank pulley bolt. i just changed my water pump last week and had to buy a new torque wrench to get the required 151lb ft of torque on that bolt. take it back and get them to pull the starter and re-tighten that bolt. you will get angry if you try to do it yourself because the starter heat sheild is held on with more huge bolts than the starter itself. you have to remove one of the torque tube to bell housing bolts just to get the heat sheild off!!!
i beleive you are correct about the crank pulley bolt. i just changed my water pump last week and had to buy a new torque wrench to get the required 151lb ft of torque on that bolt. take it back and get them to pull the starter and re-tighten that bolt. you will get angry if you try to do it yourself because the starter heat sheild is held on with more huge bolts than the starter itself. you have to remove one of the torque tube to bell housing bolts just to get the heat sheild off!!!
11-08-2002, 03:11 PM
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Take it back as soon as possible. Most likely the did not torqued the bolt to spec...
You do dot want to push the car without proper lubrication...
And I agree, not something you would like to tackle yourself... let the shop that did the work fix it.
You do dot want to push the car without proper lubrication...
And I agree, not something you would like to tackle yourself... let the shop that did the work fix it.
11-08-2002, 04:34 PM
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bs, you don't have to remove anything involving the torque tube to remove the heat shield, only have to loosen those two bolts the head shield is slotted at that end, at least mine was. At first I though, oh man I have to remove the toque tube to get a stupid heat shield off, not so, justloosen those two huge heat shield bolts and the two smaller ones on the starter and slide the shield towards the back of the car.
11-09-2002, 06:26 PM
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Thanks guys for the replies!
I took the car back to the shop that changed the belts and the waterpump. They insisted that the crankshaft pulley bolt was tightened to the correct specifications. I insisted that they do it again. I picked up the car later that afternoon after they re-torqued the bolt. The same problem was still occuring (very erratic and low-to-no oil pressure. That was Friday. Saturday I decided to torque the bolt myself, after removing the starter, which seemed to have not been removed for years. I held the flywheel in place with a screwdriver while my neighbor tightened ( a lot ) the bolt to the correct specifications (154 lbs-ft). The bolt was not anywhere near the correct tightness. I got back in my car and started it and, well, what do you know, instant oil pressure!! The problem was fixed. The shop has a lot of explaining to do!!!
I hope this helps anyone else with the same problem.
Kelly 1987 944
I took the car back to the shop that changed the belts and the waterpump. They insisted that the crankshaft pulley bolt was tightened to the correct specifications. I insisted that they do it again. I picked up the car later that afternoon after they re-torqued the bolt. The same problem was still occuring (very erratic and low-to-no oil pressure. That was Friday. Saturday I decided to torque the bolt myself, after removing the starter, which seemed to have not been removed for years. I held the flywheel in place with a screwdriver while my neighbor tightened ( a lot ) the bolt to the correct specifications (154 lbs-ft). The bolt was not anywhere near the correct tightness. I got back in my car and started it and, well, what do you know, instant oil pressure!! The problem was fixed. The shop has a lot of explaining to do!!!
I hope this helps anyone else with the same problem.
Kelly 1987 944
11-09-2002, 07:26 PM
#7
Nordschleife Master
[quote]Originally posted by Tabor Kelly:
<strong>what is the shop called? where are they located?</strong><hr></blockquote>
Yeah...that definetely sounds like a shop to add to the AVOID list..
<strong>what is the shop called? where are they located?</strong><hr></blockquote>
Yeah...that definetely sounds like a shop to add to the AVOID list..
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11-09-2002, 07:59 PM
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The shop was:
South Main Auto Service, Inc.
Blacksburg, VA (USA)
It is part of a nationwide chain of automotive shops under the name:
American Car Care Centers
I thought I was safe taking the car to a nationwide chain. I guess I was wrong!
Again, I hope this helps anyone else.
Kelly
'87 944
South Main Auto Service, Inc.
Blacksburg, VA (USA)
It is part of a nationwide chain of automotive shops under the name:
American Car Care Centers
I thought I was safe taking the car to a nationwide chain. I guess I was wrong!
Again, I hope this helps anyone else.
Kelly
'87 944
11-09-2002, 08:26 PM
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LT:
maybe there are different versions of the heat sheild... mine was held on by those 2 bolts that only have to be loosended (my wastegate would have had to be removed to get them all the way out) AND also mounted to the lower left torque tube bolt. and that was a solid hole, not a slot, so the bolt really did have to come completely out.
Kelly:
i think you should get used to taking your car ONLY to a mechanic that deals with porsches. these cars are not as idiot-proof as a POS gm that these guys who dropped out of high school to wrench on their camaros can touch without breaking stuff. i'm sure those guys haven't looked up a torque spec or used a calibrated torque wrench in years. they probably just got jim-bob to hold the alternator pulley while earl banged on a crescent wrench with a hammer.
don't go back there again.
maybe there are different versions of the heat sheild... mine was held on by those 2 bolts that only have to be loosended (my wastegate would have had to be removed to get them all the way out) AND also mounted to the lower left torque tube bolt. and that was a solid hole, not a slot, so the bolt really did have to come completely out.
Kelly:
i think you should get used to taking your car ONLY to a mechanic that deals with porsches. these cars are not as idiot-proof as a POS gm that these guys who dropped out of high school to wrench on their camaros can touch without breaking stuff. i'm sure those guys haven't looked up a torque spec or used a calibrated torque wrench in years. they probably just got jim-bob to hold the alternator pulley while earl banged on a crescent wrench with a hammer.
don't go back there again.
