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lost oil pressure help please

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TonyPanchot

TonyPanchot

Jedi Trainee
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Now what ??

started the 250 last night and the red light is on and reading no oil pressure

put on 100 + miles last weekend with no problem

no odd sounds, looked under filler cap and can see no visible oil on the rockers
changed oil (vr1 20-50) and filter (KN High-performance) 30 days ago including a 6 oil pump, cleaned the sump, new spring and plunger for the pressure valve even installed a new warning
sending unit

any ideas guys ? its going to be a great weekend here and need to get out on the road
 
Change the filter first, and crank the car with the plugs out and see if you can get the pressure up. . If not, then it is probably off with the sump to inspect the pump. Perhaps it has failed. Sorry for the bad news...
 
I know nothing about 6-cyl TRs -- do they have a mechanical pressure gauge like the 4-cyl or do they use a sending unit like 'modern' cars?

If the latter I would start by inspecting the sender and its circuit (but then I am an optimist by nature).
 
Does you car have a mechanical gauge, electric, or just a light? If it were me, I'd temporarily install a cheapy mechanical gauge, remove the plugs, and crank it. It should register something. I keep a gauge in my tool box just for this purpose.
 
Tony, are you saying that the oil pressure gauge is not reading any pressure?? That gauge is not electrical, but is hard piped in. If you are not getting any pressure there, then it is time to pull the sump and the pump.

Did you install a new pump?? I've read of instances of these new pumps shearing off the pin that holds one of the rotors on.

Edit: One more thought, maybe the spring broke on the pressure relief valve. Easy enough to check.
 
I would certainly suspect the sender unit first. Do you have the old one you could substitute?
 
TonyPanchot said:
the red light is on and reading no oil pressure
Click to expand...
If you've got both the light and the gauge indicating no pressure, it's a safe bet you've got no pressure. IMO the very next step is to drop the pan and find out why. With any luck you haven't ruined any bearing surfaces yet, but if there is no oil flow through the rod bearings you aren't far from a spun bearing or worse.

When it happened to my TR3A, the problem turned out to be a con rod locktab that had broken off and found it's way into the oil pump. Pump seized and sheared off the drive tang, but all I heard was a very slight change in the tone of the usual engine noise (was doing about 70 mph at the time). Shut it down ASAP and towed it home. The bearing inserts had just barely started to break up, they probably could have been reused (but I replaced them anyway). Fortunately all the crank surfaces were OK, so I didn't have to pull the engine.

And for some reason I don't use locktabs on con rods any more!
 
TR3driver said:
...

When it happened to my TR3A, the problem turned out to be a con rod locktab that had broken off and found it's way into the oil pump...
Click to expand...

How the heck did the con rod tab find it's way through the screen on the oil pump?? :confuse:
 
martx-5 said:
How the heck did the con rod tab find it's way through the screen on the oil pump?? :confuse:
Click to expand...
The original type TRactor motor screens are very prone to break after long service, around the solder blob that holds the screen to the pickup tube. Under engine vibration the individual wires tend to flex right at the surface of the solder, so they eventually work harden and break. My screen was still original ...

Somewhere I found a tip to reinforce the screen by threading safety wire through the screen and around the pickup. Maybe it was in TRSC's Tech Talk, don't recall for sure. Anyway I did replace the screen and reinforce the new one.
 
All stock guys

and I just pitched the old unit as I thought the new would do the trick
have not driven it any where started it up and the light came on and no pressure build up
checked under the fill cap an no oil splashing about

shut her down

tried again this am and the same ( as if I was hoping the garage gremlins would fix for me )

ok well I am going to put on the working cloths have a beer and put her on the stands
 
ok pan pulled and no metal in the sump and oil looked good (3 weeks old)(200 miles)
oil pump is firmly attached
pulled the pump and all looks good with no scoring
do have a question
how far down should the pick up be
what I mean is mine is showing 1/2 in. of thread

but my dip stick was reading to the top of the second mark

and was parked on level ground when I started it
 
Ok here are the results

seems like a failed oil filter is to blame
I have the spin on adapter and normally use the fram ph 3600
when I did the oil change I up graded to the K & N HP 2009

well it seems that it lasted 200 miles or so
talked to the folks at K & N and I am sending it back to them for testing

All is well now and going to take he for a spin in a bit
 
I have no ideal other than was no flow thru the filter ??
took it for a drive and all is well
 
On real weird from 1 to 10 that is at least a 9.2!!!! I did see a filter failure that cost a motor once years ago,the outer casing of the cartridge came off at speed,by the time the idiot lamp came on it was all over....
MD(mad dog)
 
Tony Just curious, did you install another K&N or did you go back to the Fram? Did K&N do the cross from the Fram PH3600?
Brian
 
I thought oil filters have an internal bypass so if the filter gets clogged, like not changed for thousands of miles pressure in the filter would increase to a set pressure point and the paper filter would releasee and oil would bypass the actual filter. in effect dirty oil is better than no oil????
 
hondo402000 said:
I thought oil filters have an internal bypass so if the filter gets clogged, like not changed for thousands of miles pressure in the filter would increase to a set pressure point and the paper filter would releasee and oil would bypass the actual filter. in effect dirty oil is better than no oil????
Click to expand...
Most (not all) do. But that doesn't necessarily protect against a mechanical failure inside the filter, for example if the paper element were crushed up against the outlet port. And the bypass pressure can be pretty high; I was looking at one the other day that said 25 psi.
 
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