I use a 1990 with a 2.9 (201,000 miles) as a daily driver. I have been having trouble with valve noise in the morning when I start it and when it gets warmed up after 10 miles of driving. I know the factory "gauge" is pretty much useless so I hooked up a mechanical gauge. It reads 40 psi at start up at idle. After I get to work, I check it at idle and it reads 9 psi. My son thinks it might be a weak pressure relief spring in the oil pump. Any ideas?

 

I doubt it. At 200,000 miles the bearings are probably just showing a lot of wear. if it isn't knocking I probably would just leave it alone it will survive just fine at idle on 9 psi.The old rule of thumb was 5 psi per for each 1000 rpm's. The problem with opening an engine with this kinda mileage is there is no place to quit.

 

Might consider a thicker oil, 30W maybe. Any engine will have greater clearances after it is warmed up, this leads to a decrease in oil pressure along with the decrease in viscosity due to temperature increase of the oil. Thus the engine is indicating high mileage.

The pressure relief valve opens if the oil is unable to go thru the oil filter.

 

I'm pretty sure you cannot find a 'mechanic in a can', but you can help the noise by using an oil with a higher viscosity. Personally, I would try a 20W50, or 10W40, and see if it reduced the noise until the viscosity increasing additives wore out.
I think the 2.9 tended to wear its cam bearings and drop pressure throughout the whole engine. The low pressure at idle should not be a problem, but will likely allow the lifters to slowly bleed down and make noise. The relief valve limits the highest pressure the system will generate when the oil is thickest, and generally closes as soon as the oil is flowing and warmed up. If you were in very cold climate, the relief might not be able to limit the highest pressure if the oil were very viscous.
I have to agree about doing a 'partial' on an engine with this many miles. Where do you stop? Just the cam bearings? Rings? Rod bearings? Crankshaft bearings? Lifters?
That engine design started out with solid valve lifters, and the hydraulic lifters were added when the displacement was increased. Most of the 2.9's I have heard has some valve noise, FWIW.
tom

 

By chance did the cold start up noise begin suddenly after some event, like an oil & fllter change????

If so, maybe suspect the oil filter, maybe it's faulty, or some brands are known to cause start up noise.

I'd use the specified Motorcraft filter.

The multi-viscosity oil you choose can vary in viscosity a good bit at 40C & 100C temps, so you could try using a brand with higher published viscosity figures at those temps & see if things improve, or step up to a higher viscosity range as has been suggested & see what happens.

Are you using a "high mileage" recipe oil???? If not, maybe consider that, in the brand oil you've been using.
The viscosity in most of those recipies tends toward the higher end of a service grade, there are additives to increase seal swell & extra detergents & anti-oxident ads to help deal with blow by that could help keep the oil viscosity in grade longer during an OCI & maybe help some with start up noise.

Seems to me that 40 psi at cold idle & 9 psi at warm idle is a little low, but not so much that the engine should be noisey at start up.

So do you know if the engine is sludged up????
Have you had the valve covers off lately, if so, how did it look under there???? I'm thinking maybe the oil pump screen is clogged up some????

More thoughts for consideration.
Let us know how it goes.

 

I would not thicken the oil. That will make the problem worse by decreasing flow to the lifters, which are probably the source of the noise. The best approach is to make sure you are using a very good filter. Most aftermarket filters are actually not even close to the Motorcraft one. The bypass valve for example. Frams can open as low as 15 psi, while the Ford one will not go into bypass till 45 psi. This means that most of the time, the Fram will be in bypass mode.

I would try this because it can remove some deposits that can contribute to the problem. Drain off one quart of oil and replace it with a quart of whats called Rislone. Leave it in there till your next oil change, then switch back to regular oil. This treatment has worked for me in the past.

 

Quote khantranitar: I would not thicken the oil. That will make the problem worse by decreasing flow to the lifters,

K, I would say that the flow to the lifters will increase, as the flow of oil that previously streamed out past the main and rod bearings will be decreased, thus leaving more oil flow available to pass on to the lifter gallery, which is usually that last place fed.
The output of the oil pump itself may be increased also, as there would be less leakage around or past the teeth of the gears. At the operating temperature, all oil is about like water in its viscosity, with some difference in the multi-weight oils.
10W-50 flows like a '10 weight' oil when cold, and has the viscosity that an oil rated at 50 would have when hot. Viscosity index improvers expand with heat, and give the oil more 'body' to increase its apparent viscosity. It will flow through a specific diameter hole at a specific rate at a specific temperature. Increase temp or the diameter, and the flow will increase. A single grade oil, such as 30 weight, will be harder to flow when the engine is cold, and have the viscosity index of a 30 weight oil at operating temperature. If you used the 20W50, you would be 20 points of measure above the 30 when at operating temperature.
Do what you will.. YMMV
tom

 

Yes, it has a good quality filter. I changed the oil from 10-30 to 15-40. With the lower grade oil, I was getting a rod knock at idle. When driving and setting at a stop and watching the oil pressure drop, the lifters bleed off and it begins to run like crap. If I keep the idle/oil pressure up it runs great. This engine runs great down the road and doesn't leak/blow oil. I have had the valve covers off and I didn't think it looked that bad for as many miles it had on it. I, like others, don't have the $$ for a rebuild or a 4.0 swap. Sooooo, I was hoping for a simple thing like an oil pump. But I might try a 20-50 if it is still made anymore.

 

20 - 50 motor oil is available. Look for it in a High Mileage formulation.

 

That's what I'll do next oil change. Where would you recommend I locate this oil? I don't think I saw it at Wallyworld, but then again, I wasn't really looking for it at the time.

 

If your are going to go to a thicker oil then I would just go to straight 30 or 40 weight in the summer and 15-40 in the winter.

 

I found it listed on BP's web site. Given the mess BP has made in the Gulf of Mexico, you may want to search some more or just forget it and follow "wtroger"'s suggestion.

 

Most regular auto parts stores should have the 20w50 oil but not all will be in a high mileage formula.