5 psi at idle after warm up??!! holy crap

[dgndngrngr]

i understand the problem with these 2.9s and how they have narrow oil passages but it seems like everyone has ticking/low pressure on start up and it goes away once it warms up...well...i have just the opposite problem.

50 psi start up
25 psi after 10 minutes idling
5psi at idle after driving around for about 10 minutes (ticking very loud)

I have been runing 10W-30, should I switch to 5W30? what it make that big of a difference?

any suggestions will be appreciated. did vaccum test today which turned out that the engine was healthy. ill do the compression test tomorrow but i havent had a problem with coolant loss yet.

 

[dgndngrngr]

also has anyone tried this?

"The ticking noise you hear, is space between the lifter and the cam lobe. What you want to do is this: Wash out that lifter by adding 12oz of gasoline to the crankcase with the engine running, to temporarily thin out the engine oil. This will wash out the lifter. After a few minutes, the gasoline will evaporate out of the PCV system; and your oil will return to it's normal viscosity. Afterwards and hopefully, a pumped up lifter will emerge maintaining zero clearance between the lifter and cam lobe."

 

[MAKG]

Sounds like a nice way to score cylinders and maybe spin a rod bearing.

In Michigan, 5W-30 will work fine, at least in winter. 10W-30 is probably fine as well. Note that the "W" number is irrelevant on a warmed engine, and both weights will behave the same at operating temperature.

This does not explain low oil pressure. The only reliable fix for that is to replace the worn parts. You can try putting in a heavier oil, but you run the risk of making it permanently worse -- wear is almost never uniform, and you might get the pressure up, but oil starve some parts of the engine because the oil won't go through the smaller holes (in particular, the lifters are worrisome, as they have the tightest clearances in the engine).

But do check for other problems, especially fouled oil due to rich running. If the problem goes away temporarily with an oil change, suspect a problem here.

 

[dgndngrngr]

thank you makg. do you think Rislone would help or just add to the problem. i know once you free up some sludge it gets caught in other places.

 

[fordktpjoe]

I've always had good luck with Lucas. But you got to replace a quart of oil with it.

That's just me though, I am sure there are those on here who hate the stuff, and even I am not sure I'd use it in the dead of winter, that stuff is thicker'n molasses!

 

[MAKG]

thank you makg. do you think Rislone would help or just add to the problem. i know once you free up some sludge it gets caught in other places.

There is some risk with any cleaner.

The safest "sludge remover" is clean engine oil. You can change oil more often if you think you need it. But I wouldn't go assuming stuff about sludge. A properly running engine that has had regular oil changes doesn't form it. And sludge does NOT make the oil pressure go down.

Lucas Mucus is almost entirely equivalent to rather expensive heavy-weight oil, with nearly the same risks and benefits.

 

[WNY964x4]

now , i do not know what makg thinks of this , but when i had my 2.9 , when i changed my oil i left the filter and added a gallon of diesel to the crankase , ran it for about 30 - 45 seconds , then shut the truck off , drained it changed the filter and filled the oil back up , never had another problem till it blew a core plug , at which point i sold it and the kid that bought it still has it

the diesel thing is something my stepdad told me to do , it may have been irrelevant , but he had a 63 Impala SS 409/425 and he did that with every oilchange , after he sold it and the buyer wrecked it , a guy bought if for the engine , he tore it down and said that it looked as if the engine had just been assembled at the factory , and that was 5 years after the car was built

 

[MAKG]

5 years after the car was built, it damn well SHOULD look like it just left the factory, even with 100,000 miles on it.

According to the next owner, I still had silver on all the crank bearings on my 2.9L, when it ate its camshaft at over 250,000 miles. And I never put Diesel in it.

Diesel isn't anywhere near as bad as gasoline (it's far more viscous), but it's still both unnecessary in most cases and not advisible.

And a GALLON is far too much. That's an entire crankcase full.

 

[WNY964x4]

well , the only thing with that 409 was it was slightly modded to make about 450 to 475 horse and it was reguraly beat on , my stepdad bought it brand new when he ws 20 , and he admits to me that he had her up to 140ish ( the speedo stopped at 120) several times , he beat the hell out of that car

 

[Sasquatch_Ryda]

A couple of times at work I've pulled a drain plug out of an oil pan only to find a slow glop of goo to slowly come out. I find adding a liter or so of ATF to the engine oil and running it up to operating temp for a bit cleans out the sludge deposits pretty well. Drain the oil and repeat again if necessary. Then replace the filter and fill it up with fresh oil.

 

[dgndngrngr]

alright thanks guys. lots of good info. this is the 2nd engine in this thing and no head problems so far...miles?...over 200k. but ill see how far it goes with the oil pressure issue before i need to open her up

 

[holyford86]

my original 280k 2.9 looked like brand new inside, and the only thing ever done to it was the oil was changed religiously every 3,000 miles. I pulled it for a much lower mileage 2.9 simply because it needed valve seals and had begun to tick on startup. Its still sitting in my garage just in case I ever need it. Poor maintenance is usually the cause of abnormally low or high oil pressure.

 

[rusty ol ranger]

Does your oil pressure increse with RPM?

You techinally only need 10PSI for every 1000rpm.

later,
Dustin

 

[np205]

Mabey it thinks it's a Detroit

 

[koldcustoms]

Sounds like a spun bearing. Oil is pouring out of the crank/rods, reducing pressure to the lifters. The same thing happened to me with another truck I owned. If this is the case, pressure should rise with engine speed and fall at idle. If not, then I'd say your pump has calved.

I'd never put fuel in the crank case. A litre will be more then the PCV system can handle. When you drain the pan, residual fuel will remain in the engine. Much of it will bond with the free carbons in the oil. It's fuel vapour combined with carbon that creates sludge.

Use an oil flushing produce to purge the system. I've used AFT with some success also. Substitute a quart of Rislone (or similar produce) with the fresh oil.