Lost oil pressure 2 miles after full rebuild

[feeley5000]

I just completed a full rebuild on my '90 awd. I used a top-line oil pump, packed the pick-up and pump gears with assembly lube, and primed the system with a drill before installing the timing belt. I used blue locktite on the bolts that attach the gear, sprockets etc to the pump, and torqued all bolts to the factory service manual specs. I did not remove the balance shafts.

I started the engine and the oil pressure was at the middle of the gauge at 2000 rpm. Everything sounded fine, I had a buddy visually inspect everything for leaks, and I took off for my break-in run.

Two miles in the factory gauge dropped to zero and the oil pressure light came on. There are no visible leaks, the dipstick reads fine, and my lifters were quiet. Any advice? Similar problems experienced?

Tomorrow I'll pick-up a mechanical test gauge to get an independent reading on the pressure. If that reads zero I'm at a loss.

 

[Talesin]

Did you retain your oil squirters? Did you replace the check valves with new units? Heard of this kind of thing happening when a check valve fails, though usually not quite that dramatically.

I assume you stopped immediately and managed to save the engine? Did you check the oil level, and how much did you put in after the build? Haven't done a rebuild myself, so don't know if packing the oil pickup with assembly lube is SOP, but that sounds a bit funky to me.

Already inspected all the belts and checked everywhere for leaks?

 

[feeley5000]

Yeah, I retained the squirters. I used lubriplate, which is a very light grease/assembly lube on the pump/pick-up.

 

[laserspeeddemon]

Check to make sure the connections on the oil pressure sender isn't broken or became unplugged. Mine did that.

 

[djmixerx]

I would run a manual oil pressure gauge. I hate looking at the factory one.

 

[jking29]

If the gauge dropped to zero and the oil light both came on, you are s.o.l. The gauge and the light use seperate senders so the chances of both of them or their wires getting screwed up at the same time or almost none. You may want to pull the pan and front cover and give everything a visual inspection before you try and start the car again.

 

[laserspeeddemon]

If the gauge dropped to zero and the oil light both came on, you are s.o.l. The gauge and the light use seperate senders so the chances of both of them or their wires getting screwed up at the same time or almost none. You may want to pull the pan and front cover and give everything a visual inspection before you try and start the car again.

Both of mine went out at the same time, but I go off-roading so I hit alot of rough terrain. My point is don't discount it. He could have ran over something that yanked it out.

That what he said is more accurate.

 

[steve]

But you have to ground the wire for the idiot light to go on not just have the wire fall off. The guage however will read 0 if the wire falls off which they do pretty often. So the odds if the one wire falling off and the other falling off and grounding are smaller than actually loosing oil pressure on a rebuild.

 

[Spoolin4Ever]

I've never built an engine, but I've read many many posts about the oil pumps, and I have never heard of packing the pickup screen with assembly lube. I would wonder of that could slow down the picking up of the oil? Could it clog up or make it not suck oil like it normally would?

I've surelt heard of packing the gears with lube, but not the pickup screen. Where did you come up with that idea? Experienced builder or your own?

Good luck and I hope it's the gauge wires or something related.

 

[nates6969]

Ya I know any assembly lube I've ever used is very thick and I could definitely see it clogging the pickup. How much lube did you actually pack in there? You might want to drain the oil to remove any thickened oil then refill it, then pull the timing and prime the pump with a drill. Also remove the turbo feed banjo bolt on the head and look for oil "pumping" out, not dripping, during priming. This will tell you if the pickup is indeed blocked.

 

[jking29]

Assembly lube mixes with oil, so if he had oil pressure when he pre-oiled it and then when he started it, I don't think that the assembly lube plugging the pick up is the problem. A quick check of the wires will tell you if both wires are off and grounding. If the wires are in place still, I would not start the motor again until everything is completely checked out visually. It's a pain in the ass, yes, but much better than losing a new motor.

 

[feeley5000]

Thanks for all the suggestions. I figured I was s.o.l with both the light on and the gauge at zero. I towed it home and haven't touched it yet. I'll pull off the pan and the timing, check the pickup, and reprime the system. I'll let you know how it turns out.

 

[feeley5000]

Sorry for the delay, I forgot to follow up. I pulled the timing belt off and trying to re-prime with a drill, no luck. Then dropped the oil pan. Low and behold, a loose pickup. Apparently we left those bolts hand tight when we put it together at 3am... In retrospect, this was consistent with my problem. It probably took 2 miles of vibration for the pickup to loosen enough that the pump sucked air.

It's back in business, so I'll assume I shut her down quickly enough to save the engine. Now I can worry about my excessive rear diff backlash.

Thanks for all the suggestions.