MichelleJD

Is there any way for a mechanic to ruin an oil pump while doing a water pump replacement? I went to pick up my 951 and when the mech fired it up it only registered 1 on the oil pressure gauge. He believed it was the sending unit and kept running the engine. When the valves started tapping VERY loud I convinced him I wasn't some stupid girl and that he should shut down the engine. So, somwhow, it looks like the oil pump is shot. Is that possible? COuld it be something else? My son was supposed to get the car grad night and now it looks like a no go. I'm so disappointed and upset. Can you guys give me an idea so I'll know what to do?

Thanx
Michelle

Skitch

Have them check the torque on the crankshaft pulley nut. I have had a similar issue with low oil pressure and this is on the list to check, they may have not tightened it enought when they put the belts back on after the water pump.

Hope it all works out!

Ski

You have used this wrench before? With good results?

This is meant to be serious: After this happened did you by chance check the oil level? Did you have an oil change done and they forget to fill it afterwards? Simple things first,,and you were leaving for FL in the a.m....

MichelleJD

The oil was changed a week before the water pump went. I had no problems with the oil. We checked the oil level before we cranked it and it was fine - that's why he thought it may have been a loose wire to the sending unit. I've been doing a search on the forums and it looks like the crank pulley nut being loose or the PS pulley being on wrong could be the culprit. I left a message with the mech to check that first thing in the morn. I was supposed to leave tonight tho'...... <img border="0" alt="[grrrrrrr]" title="" src="graemlins/cussing.gif" />

Peckster

It sure is hard to find a good 944 mechanic.

The bit about your guy waiting until the tappets got very loud, combined with the low pressure reading, is alarming.

I wonder if it might affect your main bearings.

Toolmaster

Michelle -

Chances are, the mechanic didn't install the rubber O-ring behind the crank gear that butts against the oil pump drive gear which in turn turns the oil pump.

Email me in the AM, and we can chat voice if you'd like some other possibilities. I'm EST here, and drive from 5:45 till like 7:30am in the car.

HTH!

Sasha

I have done the water pump before, I don't see how one could mess up oil pump while working on the water pump.

The bolt on the crankshaft has thread that is the opposite to the rotation of the crankshaft - loose bolt will have a tendency to tighten...

Besides there is a "key" on the crankshaft that would prevent the pulley from spinning freely...

The cranksaft pully (as I understand it drives belts for a/c - alternator and PS) is not required to drive the oil pump...

When the sender unit fails it reads "high" oil pressure ( I think - because the higher the pressure the more resistance the unit produces - when it fails resistance is infinite). I had one failed...

Simply if your oil level is normal but no pressure, oil pump is to blame.

Of course I may be wrong - all the above is just speculations...

Thanks.

zakk

The torqued down crankshaft bolt is required to drive the oil pump. It's not fed via a belt or anything, it's behind the pulleys and drive gears and will only engage when the big bolt is sufficiently torqued down. Doing the water pump requires taking off the rear timing cover, which requires undoing the big crank bolt to get all that stuff off, the guy probably didn't follow the torque spec when putting it back on. Yell etc.

MichelleJD

Thanx guys. I'll be steadily praying tonight.....

Ahmet

The PS pump pulley applies torque to the crank pulley (counter clock) to loosen the bolt. That bolt should have loctite on it, and be very tight. When pulling the pulleys, there's a washer, I'm not sure if I'd call it an o-ring, if this isn't replaced, it could also cause low oil pressure, as mentioned above, however he should not have had to do this for just a waterpump, unless you asked him to do your front seals also.
Ahmet

zakk

Loctite? the factory manual doesn't specify loctite for the crank bolt, just 155 ft/lbs of torque. I've seen many people advise against loctite on that bolt since it tends to make it nearly impossible to get off the next time you need to do so. I suppose it's good insurance if you don't mind that trade off tho.

SidViscous

Damn Michelle, that sucks. Have no advise, but I'd definitely ream the Mech.

Just gives me more incentive to do the timing belt myself. Might still screw it up but at least I have no-one to blame but me.

Just talking about the crankshaft bolt.

When I changed the cam in my slant 6 I couldn't find it on re-assembly, turns out it wasn't on to begin with. I put 20k miles without it before and I've put 10k miles on it since.

The Duster aint no Porsche, but it beats it hands down on staying running

Hell changing the oil and tranny fluid is considered a bad thing

Good Luck Michelle, hope you make it to Fla. If you do have a marg on me.

Martin

There is no rubber O-ring or similar, As mentioned above the mechanic would have had to undo the crank bolt to get at the belts. The oil pump is friction drive only from the back of the cam belt sprocket through one flat washer (that can't be missing unless the key was removed from the crankshaft) direct to a tube drive impellor for the pump, The oil pump will not turn effectivly if there is less than 50 lb/ft on the crank bolt. The bolt is supposed to be tightened to 155 lb/ft. The thread is a standard clockwise thread which will undo by itself if not tightened enough. To loosen this bolt (just did the oil pump seal) I use the starter motor to turn the motor against a chocked socket and bar. To tighten it without the use of a flywheel lock I put the car into fourth gear with the park brake applied tightly. (I must get a flywheel lock)
I am suprised your mechanic left it running without oil pressure, the procedure that I use and many others will suggest is to disconnect the coil HT lead and ground it so the car will not fire, then crank the starter in 20 second bursts until oil pressure reads on the gauge.
There will be nothing wrong with your oil pump. At least it is an easy fix, get your gar out of there as soon as you can.

944Targa-fan

In response to Martins post; after the oil pump drive gear an o-ring is installed. Then a washer is installed etc.

<a href="http://www.pelicanparts.com/944/944_parts/944_83-85/pic2.jpg" target="_blank">http://www.pelicanparts.com/944/944_parts/944_83-85/pic2.jpg</a>

Part # 4 is the o-ring

When I rebuild my ’86 engine it also had an o-ring installed after the oil pump drive gear. So it’s not just for the early models.

Your mechanic could have screwed up your oil-pump if he; forgot the washer/o-ring, installed the parts in the wrong order, set the torque wrong (using an air-wrench or something similar)

tifosiman

Is this the same mechanic that you had problems with before on your N/A?

Tifo