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Triumph TR6 - oil pressure

I have a 1976 TR6. The previous owner had not changed anti freeze for some time so I had the local rad shop flush the cooling system and change to new anti freeze. It was very rusty and grimey. Since this has been done the oil pressure has risen dramatically. Cold at 100lbs and once warmed up around 75lbs. I do not remember the previous pressures but they were what I considered to be normal and did not catch my attention, probably around 60lbs etc. I am aware that too high oil pressure is not a good thing, but what could be the probable cause of this, and how is it corrected. Thank You, Dave
David B

Hi David

congrats on having the finest year of the TR6 (tee-he-he).... wife says this is sure to start a fight... but I just can't help speaking the truth...!

Oil preasure has likely risen due to much better engine cooling capabilitiesafter the flush... viscosity will decrease , thus pressure decrease, with overly elivated engine temperatures... think what a new radiator might do for the car?! You may wish to check the presure relief valve for correct operation, however , as the oil pressure sounds just a tad high... could be a somewhat faulty gauge too. A new PR kit, consisting of a spring ,plunger, and washer is quite inexpensive and easy to install... ensure that the bore is smooth and clean in which the PR valve is to slide into.... smear some Lubriplate or equivelent on the plunger upon assembly into the bore.Hope this helps.

Cheers, Rob
'76 CF57639UO

PS last week I met a fellow living only a block away with a TR6 com# cf57636u ... can you beat that? I think that there are about 6 TR6's within a two minute drive of my house!
Rob Gibbs

Rob, maybe immitation IS the greatest form of flattery.
Gene Holtzclaw

I agree with the more efficient cooling when the engine is warmed up. But it shouldn't influence the cold start where you are seeing 100psi.

Is the gage pegged? Was there anything else at all done to the engine? oil change with higher viscosity oil then you are used to using?

I agree the pressure relief valve could be stuck. It's easy to remove and no oil will spill out...well maybe a drop.

They didn't do an engine oil system flush did they? I hope not.

Let us know what you find.

HP Henry Patterson

Thank you for your suggestions. I agree that the oil viscosity is the same with the engine cold so the pressure should not have changed. I am busy getting another car ready for the British V8 Meet in Townsend and MG2006 in Gatlinburg in a couple of weeks. The TR has been put on the back burner for now. I now suspect the oil pressure relief valve. There have been no other changes except for crank thrust washers which were changed far before the rad flush. Henry, what is a pegged guage? It worked well before, and still acts normal except for the high readings. I appreciate everybodys imput, this is a great bulletin board! Dave
David B

Replacing the thrust washers is likely to make a change. Might you be more sensitive to the readings since the rad flush and the 'warm' pressure also make it more noticable?

Sure, do the PR kit but as any good criminologist will tell you, an eye witness is the worst evidence you can have. :)

No offense intended but 75 lbs warm isn't way out. A tired gauge can easily be off by 25%.


EC Smith

Since I did my lower bearings,oil pump and thrust washers my pressure hits almost 100 when cold drops down to 80 when driving and sits at 50 when hot at idle.
Before that it peaked about 70 when cold. I cleaned my relief valve and checked the length of the spring etc
I don't think you have a problem

Charlie B.


What I mean by "pegged" gage is...does the needle go past 100psi until it can't go any further because of a mechanical stop? I doubt that's the case though.

My readings are like Charlie B's after I did my rebuild. But I still don't see how you had a dramatic rise righ after a cooling system flush.

HP Henry Patterson

Someone complaining about good oil pressure in a TR6!

Dave, I have a little difficulty thinking that a rad flush will change your oil pressure that much. I am not sure if you say your pressure went from 60 to 100 or 60 to 75 LBS?....Is the previous 60LBS. cold or hot? I would think you would also be talking here about a non operational temp gauge now....not pegged at overheat!
After my engine job, I am identical readings as Charlie. Before at hot I was around 30 LBS. ( the engine was definitely saying something to me along with doing some compression readings:).
Your pressure sounds just fine.
Drive her and have fun.

Rob Gibbs, they must have been parked beside each other on the boat trip over.

P.S. '71 was the finest year for the TR6.
Rick C
Rick Crawford

This thread was discussed between 23/05/2006 and 26/05/2006

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