No Oil Pressure, Any Ideas?

TurboDiverArt

The Guru Thorn
Joined
Nov 8, 2002
OK, here?s a question. Had a problem at E-Town on Sunday. Car ran beautifully on Saturday, made 3, 9.8 second passes at 21 psi of boost to finish up my competition license runs (yeah!). I was very excited as all 3 passes were within about 3 hundredths of each other and at low boost, I was ready! Anyway, changed the oil/filter at the track on Saturday and all was clean. I have been fighting a smell in the car, the smell of antifreeze but couldn?t seem to locate the problem. Since smelling it I?ve done 5 compression tests (after each day of racing) with no change. I?ve done one cold compression test just for the hell of it, no problem there, fairly in line with the hot ones, just a little lower compression. I always change the oil/filter after each day of racing, never a hint of water in the oil. I?ve compression tested the cooling system (when it?s cold), pumped it up to 22 psi and it held for an hour (lost one psi of pressure but that?s OK). I was planning to pull the heads in the off season anyway and replace the head gaskets!

Anyway, back to the real dilemma. After racing on Saturday I changed the oil/filter at the track like I always do and all was clean. Start back up all is normal I have ?normal? pressure and I pull it back into the trailer and strap it down. Sunday I start the car in the trailer and I have half the oil pressure I ?normally? have. I think this is strange, I rev it a little to 1800 RPM?s and it goes up to 40 psi which is normal for the engine (yeah I know that?s low). Anyway I think to myself that it?s low but does go back up to ?normal? at 1800, I?ll keep my eye on it. I do and when hot oil pressure is normal so I feel pretty good (I run non-synthetic Castrol GTX 20-50). I go to tech and all is fine. They call the quick 16 to the lanes, all is fine. We eventually move and I get to under the tower and all of a sudden, no oil pressure! Naturally I shut down and get pulled back to the trailer. We checked the sending unit and that?s OK. Car was idling fine, no rough idle, knocking, temp was 165 which was good, no problem except the gauge read zero! In the lanes I thought it was either the oil pump belt (which I checked in the lanes) or the sending unit. All were functioning properly!

I haven?t gotten the car off the trailer yet and down to Rich?s Custom Auto but I have a few ideas to check out. My car runs with a Duttweiler oiling system (external pump, not a dry sump). Things I?m planning to check when I can get it into the shop are, clogged feed line from the pan (I?ll also look into the pan from the AN 10 fitting). Check that the pump is pumping oil from the pan. Ensure that oil was making it through the oil cooler and filter. I?ll check this from the turbo feed line as well as the block feed line. I believe there may also be an oil pressure screw on the pump but I have never looked at this before. Maybe the set screw (if there is one) backed out. Naturally being external I can just hook the pump to a drill so as not to start the engine and possibly do more damage. If oil is getting to the block then I know the pressure problem is something in the block and not with the oiling system itself. Someone at the track suggested possibly the rear cam bearing may have spun a few degrees which would block the oil passage to the sending unit.

I definitely do have a blown head gasket now as at the track I changed oil (on Sunday) for the hell of it and it was green. I had just recently put in a little antifreeze as it was getting cold and the car was being left in the trailer since I was racing every weekend or Wednesday since Bristol.

Any other ideas to check? Sorry so long!
 
Art,

With a blown headgasket, i would think depending on how much coolant is in engine, this would effect oil pressure.
 
Art,
Chech the AN 12 fitting that goes from the pan to the Dutt. pump. If the AN fitting is slightly loose, it may not leak oil to the ground, but could cause air to enter the inlet side of the pump. This happened to me personally causing little to no oil pressure and driving me crazy. You said that you had no oil pressure before the blown head gasket, but if you have coolant in the oil, that could also be your problem....
 
Maybe the set screws backed off on the oil pump drive.We use to check ours after every race. Or the relief valve has got crap in it.
Do you ever cut the filters apart to inspect them?
I do it all the time so i know if its hurting itself before i trash the motor:eek:
 
I thought about the antifreeze being thinner than oil and could lower oil pressure but I'm not 100% sure it could drop it to zero. Didn't think about a lose oil feed line, I'll check that too. Need to get the car out of the trailer and to Rich's Custom Auto. Damn shop is backed up right now, even location 2 is standing room only. Once I can get it there, Rich and I can start ripping things apart and figuring out what's up.

Thanks for the suggestions, keep them coming if you think of anymore!
 
oil pressure

Art I have had this problem twice once it was the Head Gasket, the next time it was a cracked cylinder. Both times oiling system filled with coolant, 0 oil pressure.

REG
 
Re: oil pressure

Originally posted by Reginald West
Art I have had this problem twice once it was the Head Gasket, the next time it was a cracked cylinder. Both times oiling system filled with coolant, 0 oil pressure.

REG
Yikes! Hope it's not a cracked cylinder. Car would be down for a while in that case and I'd probably be divorced.... :eek:

Surprised that antifreeze could cause no pressure but if it's happened to others then who am I to argue. I'm pretty sure a head gasket is shot as I can hear it. I was hearing something for weeks that I initially thought was a head gasket but the cylinders and cooling system were passing pressure tests so I assumed it was a header leak. It's definitely loud and coming from the passenger side of the motor under the header. I felt around but couldn't feel anything at idle, besides it's really hot under there..... :)

Thanks for the info!
 
Art,

If your running any antifreeze it will destroy the bearings in short order. The longer they run/soak in it the worse. You may have spun a bearing due the water/antifreeze contamination.. Although to completely have zero oil pressure is strange..
 
I agree, you are correct! I?ve always changed the oil the same day I'm done racing and put in fresh oil/filter and only start it to get pressure back then shut the car down being ready for the next day of racing. If it's not a spun bearing or internal problem in the motor I'm hoping that this procedure helped. Car takes quite a bit of oil at 2 gallons per oil change. Bearings are not making noise so this might be a good thing, just the now certain sound of the blown head gasket. I first need to find out why I've got no oil pressure and then access any damage that was done. There is no oil or filter in the car now. After I drained the oil when the problem occurred at the track, I left it empty when I realized there was antifreeze in the oil.

Thanks for the info!
 
Also check to make sure you didn't shear a roll pin in the cam sensor drive gear. I believe the car will still run with the cam sensor not spinning at full speed ( correct me if I'm wrong)

I'm having a hard time believing that coolant in the oil would cause zero pressure, and that is based on my personal experience. :( And the man is right on....anti freeze will kill a set of bearings in a heart beat.
Dale
 
Originally posted by Bad as L
Also check to make sure you didn't shear a roll pin in the cam sensor drive gear. I believe the car will still run with the cam sensor not spinning at full speed ( correct me if I'm wrong)

I'm having a hard time believing that coolant in the oil would cause zero pressure, and that is based on my personal experience. :( And the man is right on....anti freeze will kill a set of bearings in a heart beat.
Dale
Hey Dale,

Why would a sheared cam sensor drive gear cause no oil pressure? My oil pump is an external belt driving unit?

Thanks for the info.
 
Noticed you said something about "checked the sending unit"!!! Do you have an electric oil pressure gauge??? My electric gauge actually began to break down and fail, until it never read anything but "0". I do not know how you checked it, but try a mechanical oil gauge at the motor and see if it is reads correctly. Air in the oil system could be to blame as well. Just to many little things it could be... Just my thought....
 
Originally posted by texasturbo
Noticed you said something about "checked the sending unit"!!! Do you have an electric oil pressure gauge??? My electric gauge actually began to break down and fail, until it never read anything but "0". I do not know how you checked it, but try a mechanical oil gauge at the motor and see if it is reads correctly. Air in the oil system could be to blame as well. Just to many little things it could be... Just my thought....
Yes, electric. I testing out the sending unit by taking an air blow gun and pressurizing it at the track, I was able to easily get the gauge to read between 60 and 100 psi with the blow gun. We tried to get a mechanical gauge to work but couldn't get it to hook up, we didn't have the correct fittings to be able to spin it on because of the orientation/height of my intake manifold. I plan on doing 2 things in the future. I want to mount one of those little really bright oil pressure lights next to my shift light as well as hook up a mechanical one under the hood incase I ever think a problem is with the electrical one going to the GNX style dash (VDO Gauges).
 
Art
My mistake....I thought you had the Dutt stock type oiling system that still runs off of the cam sensor. I have seen the roll pin in the distributor shaft shear and then the gear free wheels wich not only stops the cam sensor but also the oil pump. But in your case that wouldn't be the problem.
Dale
 
Originally posted by Bad as L
Art
My mistake....I thought you had the Dutt stock type oiling system that still runs off of the cam sensor. I have seen the roll pin in the distributor shaft shear and then the gear free wheels wich not only stops the cam sensor but also the oil pump. But in your case that wouldn't be the problem.
Dale
Ahhh, there's the confusion on both our parts. Mine is a Dutt external oiling system but mine's run from the crank pully via a Gilmer belt. I've never seen another one so I assumed all Dutt oiling systems were belt driven. Learn something new every day...... :D
 
Hi All,

Finally got around to investigating into the problem with the car. Apparently the antifreeze/oil mixture from the blown head gasket congealed in the oil filter. I checked the flow coming out of the oil pumps bypass distribution block and tons of oil flows out and none goes through the bypass. When I plugged the oil feed line back into the cooler/filter system very little oil went through the cooler/filter combo and most of the oil went out the bypass back to the oil pan. I pulled the oil filter and turned it upside down and very little oil came out. Filter is still pretty much full and heavy but nothing?s really coming out. I had checked the oil pan feed screen and it was not clogged and all looked good. I also checked in the pan with a small mirror and light and I didn?t see any metal so that was a good thing as well. I changed the oil filter and hooked everything up and got my oil pressure back by turning the oil pump with a drill. I?m planning to cut the filter open just to make sure it?s just antifreeze sludge in there. Just goes to show you how quickly antifreeze in the oil can cause a problem. I had maybe 10-15 minutes tops of running time on the new oil and filter change over about 12 hours time for it to congeal up in the filter! :mad:

Thanks for everyone that had suggestions.
 
Originally posted by njturbo
Art,

With a blown headgasket, i would think depending on how much coolant is in engine, this would effect oil pressure.

Art,

I was really thinking this was a cause. Hopefully no internall damage.
 
Don't worry Artie we'll fix her here at Rich's Auto........it can be one of our winter projects, we'll have some fun with it and if we screw it up ya know what I always say......"Ain't my car so what do I care".........lol. Just kidding.
 
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