Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[DougM]

After running fine for about 30 minutes the engine's oil pressure, when idling, drops down to near zero and the oil light comes on. This problem started about 3 weeks ago. The crankcase is full with the right viscocity oil. Is there any history of the oil pump failing only when the engine is warm? Is there another pressure valve or something I need to check? If so, where is it located? If the oil pump is bad, is there any guidance on the procedure for changing it?

Thanks in advance for you help!!!
Doug

[DaveL]

What model and year Omega are you talking about ?

Where abouts are you?
DaveL

[DougM]

2001 Cadillac Catera(MV6) 3.0L Chicago, IL

[Marks DTM Calib]

The oil pump has two relief valves, a pressure relief valve and a safety valve.

If either of these stick open then you can get low oil pressure.

Also, if an oil pump is excessively worn then the same symptoms can occur, on a recent engine where we saw this, close inspection of the removed heads sudgested that it had not been well maintained and had suffered as a result of poor servicing (very few oil changes), this we suspect had worn the pump to and resulted in the low oil pressure.

You have to remember that the oil pump pumps un-filtered oil so it gets the brunt of poor maintenance.

[Kevin Wood]

Out of interest, what does the safety valve do? Is it just another pressure relief valve in parallel with the main relief valve or something more clever?

Not come across an engine with one of those before.

Kevin

[DougM]

Where can I locate instructions for changing the oil pump? Do you know of a mail order house that would carry the pump? I bought this car used and do not know what maintenance it had prior to my purchase so I am assuming the pump is the problem.

[Kevin Wood]

I would check for a sticking pressure relief valve first. I'd also double check the pressure by connecting a mechanical gauge. If you're using the car's oil pressure gauge it could be a faulty sensor. Having said that, if the oil pressure light is driven by an independant switch that's unlikely.

Next thing to check would be to drop the sump and check the pickup strainer is clear and the pipe is not cracked or otherwise damaged and is sealed to the oil pump OK.

Oil pump change will require removal of the sump in any case so it makes sense to verify this. I don't have experience of this particular engine but changing the oil pump will require a fair bit of sripping down around the nose of the crank so you'll need the belts off, rear timing belt cover, front crank pulley and seal.

If the engine has showed any signs of oil starvation - knocking bearings, noisy lifters, etc. it might not make sense to go to all the work of changing the oil pump without removing the engine and stripping it to check for bearing damage. At that point a 2nd hand engine might be a better option.

Simple things first, though.. Sticking Vauxhall pressure relief valves are not unheard of.

Kevin

[DougM]

Thank you for sharing your knowledge and I think you are right about checking the pressure relief valves first since I do not show any signs oil starvation. Where are the relief valves located? I can clean them this weekend.

It sounds as if replacing the oil pump is a major job. If it is the problem I think I'd be better off getting a new motor. The Catera never really became popular here and there aren't many of them around so finding a used motor here is almost impossible. For that matter finding any parts, new or used, for this thing is very difficult.

Thanks again for you help!!!

Doug