94 timing belt oil pump problem help!
 

hi,
I will explain best I can. We replaced the oring due to a leak. It was still leaking so we replaced the oil pump. It ran for a little while. Oil light was on, but ran great. Went to start one day and wouldn't turn over timing belt was loose. Center of pulley was stripped and new oil pump bad. Oil pump replaced. Drove for 2 weeks, ran good no leaks, now again same thing. What could be causing this? Are we not quite getting the timing belt set right? I can't imagine we got 2 bad oil pumps. Any suggestions?

Before the o'ring fix was the engine running OK other then the leak? No oil light on?

What do you mean by center pulley stripped, center of oil pump pulley? As in the pump shaft was no longer was firmly attached to the pulley?

Did you buy the replacement pump complete with housing that bolts to the engine block or pump assy alone (assy with gears).

What is the new problem in detail, pump bad how, pump pulley stripped again?

If you purchased the pump and housing as one unit did you unbolt the bad pump from the housing and look at the gears for signs of over heating?

If the pump alone, did you install it correctly in the housing.

Do you still have the old pump and housing? It is possible to easily replace the drive shaft seal on the pump which was most likely the source of the leak. Then reuse all original parts.

Any other parts changed when replacing the pump including belt.

HI,

everything was running fine. just a massive oil leak due to oring and oil pump. the new oil pump didn't come with the oil pump pulley. Yes, the pump shaft was no longer attached. We got a new pulley and attached it. We bought melling oil pump(m-183) the first time with no gear. Took everything off this time. The gear actually broke. in the center so between the center and one of the holes there is now no metal. Husband did not take off the oil pump to see is it was broken this time. He thought maybe he torked gear to tight both times or some how did something wrong. The first time he took the pulley off the old pump and put it on the new one. The second time we got one and put it on the new pump. we have reorder a new pump with a gear attached. with a whole new gasket set. My concern is something else is causing it to lock up and break and we will replace it this time only to have the same problem. Mechanic said would be about $600 if we took it in. We did not replace anything else. Timing belt is in good condition. Hope all this makes sense. Thank you.

Just covering all the bases thus have to ask.

If you have still have the old pump now having the now damaged pulley hole (round), take out what bolts remain holding the pump unit to the larger housing (that bolts to engine), remove the pump and look at the gears and drive shaft.

The pump drive shaft has no bearing other then the aluminum pump housing serving as a bearing. This shaft/housing "bearing" surface is lubed by the oil inside the pump. A lip seal between the drive shaft and housing prevents this oil from leaking out of the pump.

The driven gear drive shift slides into the pump housing and retained by the pulley being bolted to the shaft. Determine if this driven gear drive shaft is now binding or frozen in the pump housing.

Meaning the pump drive shaft froze up (or perhaps pump gears) and the pulley being powered by the timing belt kept turning. The semi-rectangle hole in the pulley being soft aluminum now sheared off forming a round hole.

If this happened after the first failure, the second pump installation might be prone to fail as the now damaged pulley had a round hole not semi-rectangle. The pulley would now be unable to fully engage the flats in the pump drive shaft. Then perhaps just a matter of time before failure.

On the first repair, were the flats on the oil pump drive shaft fully seating into the semi-rectangle cut outs of the hole in the pulley? The flats on the drive shaft need to fully engage the cut outs in the pulley hole to drive the pump on a continued basis.

Not sure if it possible to reverse pulley installation but?

Nut torque is 21 lb-ft which is not that great so possible to over tighten.

As the new part includes the pulley torquing is not required.

Before installing the part consider adding a little oil to the pump gears via the oil pump intake port, turning gears when adding it. This oil will seal up the air space between the back of the gears and housing to allowing for better priming at first engine start.

Before installing the oil pan pickup tube, clean off all excess oil from the mating surfaces of the pump housing and oil pickup tube. Use a solvent. This seal needs to be air tight or air will be sucked in causing the pump to fail to prime or deprime.

Although the initial oil leak was common, the issues with the replacement pump are not.

hi I believe it did shear off but hubby is fixing it. I will show him your post. Will replacing all of the pump fix the problem so it doesn't fail again or is there simethingelse we should replacewell?th

If you are replacing the oil pump with pulley already attached and pump already installed in the housing that bolts to engine as one complete unit, there is not much left oil pump wise.

Take note if when the water was replace, if never and the car has 150,000 miles might consider it or give it turn to check for bearing issues plus lock for leakage on the drive shaft.

If the same timing belt is used check teeth for possible damage if the oil pump drive shaft did freeze up.

The upper timing cover and engine mount can be left off when first starting engine to check for problems but button things up before driving.

Be sure to investigate the old oil pumps and pulley for damage to find out what happened.

Take note as stated a new oil pump may not prime due to clearance between gears and housing. This is why many people apply a little grease in these spaces plus between gear ends and housing before installing the pump into the housing. The grease forms an air tight seal. In your case making sure some oil is in the pump gearing should do the trick. Read any instructions with the part to determine what the manufacturer states.

If no prime, and no other issues the oil pressure light can come on. This has happened on pump replacement.