*sigh

brainhop · 10-19-2005, 05:52 AM

After getting my car back from all the belt replacements ect, and something not feeling right and the car nose diving at 4100 rpm when cold, after them readjusting everything I have driven the car twice and anti-freeze dumping out and now they say the water pump is out and needs to be replaced,

my question is there anything that they could of done like the belt to tight that would cause excessive wear on the water pump that would make it go out after they just worked on it ?

I told them when they went in there was a coolant leak and to fix it and they said it was just a 7.00 seal now there saying it needs to replaced and going to charge me an additional 8 hours work plus the cost of the water pump.*sigh.

Lawrence Coppari · 10-19-2005, 09:59 AM

It's hard to believe that a belt that is too tight would kill a bearing in two outings. My guess is the pump was on its way out, and the leakage now is just a coincidence. Bad luck.

I don't drive mine at 4100 rpms when the engine is cold.

brainhop · 10-19-2005, 10:02 AM

I usually baby it also, but thats besides the point.

I do believe that the belt caused the bearings to go out premature, what other damage could the belt do if it was way to tight ?

Lawrence Coppari · 10-19-2005, 10:08 AM

Then why did you ask about the pump bearings if you already knew the answer? Did you check the tension of the belt? How do you know it was too tight? Did you try to twist it and couldn't?

You brought up the 4100 rpms. I commented about it.

brainhop · 10-19-2005, 10:13 AM

I didnt know when I asked the question for sure sorry. The shop confirmed it.

Do you know what other damage a tight belt could cause ?

Lawrence Coppari · 10-19-2005, 10:49 AM

Like you said, it does put a bigger load on the bearings. Whether that was the cause of the pump going out is not clear. If the water pump shaft wiggles, then the bearing are gone. That will ruin the seal. If the shaft does not wiggle, then it was just time for the seal to go south. I imagine the least robust bearings are the tensioner bearing that is closest to the water pump and the water pump bearing. But when you look at the way the system turns, the pump and tensioner bearings are on the slack side of the belt. The biggest load is between the crankshaft and cam tower. It is a straight shot from one to the other. Any streaching there allows for less tension on the side that turns the water pump.

By overtensioning the belt, the belt itself could be harmed. If I were you and they admit their error, I would ask for a new belt. Maybe you could get a new belt tensioner out of them as well.

The tensioner can be mounted backwards. One side has a lip. There also is a specified direction you turn the tensioner to tighten the belt. It is the opposite direction that the tensioner for the balance shafts is turned to tighten that belt.

Sounds like they really overtightened it.

brainhop · 10-19-2005, 11:42 AM

ok thank you so much for that info, so just those 2 other things would be effected nothing internally ?

Lawrence Coppari · 10-19-2005, 02:10 PM

No, so long as the belt did not slip there would be no damage internally. The bearings on the crankshaft and cam are robust. If the cam belt breaks or loses some teeth, the timing between the valves and pistions gets out of whack. They both try to occupy the same space with bad results. But you already knew this - interference engine.

brainhop · 10-21-2005, 08:10 AM

ok now they are saying they didnt tighten the belt to tight they put on another belt one tooth wrong or something, he explained it as the belt or adjustment that controls the vibration on the 944. I dont know what that means.

Im waiting to hear back from him for a better explanation. If you know what this does what problems could be caused by this ?

Lawrence Coppari · 10-21-2005, 08:51 AM

Car has two balance shafts that rotate at twice engine speed. It is easy to misalign the lower shaft. I've misaligned it a time or two myself. There is no worry about damage to engine with a balance shaft belt off a tooth or so. It just causes a very noticeable vibration.

Only the cam belt can cause immediate damage. There are two belts on the front of the engine. You cannot see them without removing the plastic cover.

brainhop · 10-21-2005, 10:39 AM

would the "immediate damage" be immediatly noticeable ?

Lawrence Coppari · 10-21-2005, 12:31 PM

Yes, when the cam belt gets too far out of time the pistons hit the valves. You end up with no compression in the cylinders where it happens. Damage is immediately noticeable.

brainhop · 10-21-2005, 12:34 PM

Thanks so much for all the information, this forum continues to be a great resource of information, and hopefully as I learr more and more about these great cars I will be able to give back!

Thanks so much.