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Triumph Repair/TR6 Oil Leak.


QUESTION: I have a 76 TR6 that has been completely rebuilt about two years ago. When the head gasket was replaced a OE style gasket was used from Victoria British, which I am sure I have used toilet paper that was thick then that gasket. Well about three weeks after being completed the gasket started to leak and was replaced with a copper gasket from cometic. It has been running ok since then, but is now leaking oil between cylinders 5 and 6 on the driver side of the block. I checked the torque on the head bolts and all is well. After checking torque I ran the engine and there was no change. I am thinking the cylinder head is warped. Any thoughts in a different direction or do you think I am in the right area? Also in town driving the engine heats up terribly fast, once out on the highway it stays fairly low. Any thoughts on what the cause of that could be?

Thanks, Corey

ANSWER: Hi Corey,

Any oil leak in that area is just crank case pressure as there is no oil pressure port in that area. First, did you check the torque with the engine stone cold? It is no use checking the torque when the engine is even a slight bit warm.

Even if you have a crankcase vent problem and have excess crankcase pressure it would not normally leak between the head and block. The valve cover, timing cover and seals would leak first.

The over heating of the engine is the most common cause of head warpage or even block warpage.
Heating up at low speeds is often a radiator problem or circulation problem. Is the radiator shroud in place? Check the thermostat to see that someone has not put in one without the end plate to block off the transfer port when open. Also put it in a pan of water and heat it up with a meat thermometer to see that it opens when it is suppose to and that it opens all the way to block off the transfer port. Do you have A/AC on this car? Is the engine fan solid or a fan clutch? If it has a fan clutch you need to check that. I found most fan clutches are unreliable. Other then electric fans, the fan is of no use above 35 MPH. So heating at low speeds can be a air volume problem.

If you have to pull the head again check that area on the block and the head with a straight edge to see if there is any warpage. Be sure to torque in two stages and work from the center toward each end.

---------- FOLLOW-UP ----------

Although there is no pressure port back there the oil still comes up through the rocker shaft tower if that port was plugged would that cause a build up of pressure that could cause a leak right there?

On the over heating, yes the fan shroud is in place, the radiator has been replaced with an aluminum radiator with an electric fan mounted to it and the stock fan has been removed due to clearance issues I was unable to run both. The thermostat has been replaced multiple times as well as the radiator cap. It is not equipped with A/C.


From what you have done, Alloy radiator and electric fan, you should not have any overheating problems in city traffic. Something is wrong.

First just replacing a thermostat does not mean it is ok. What temp thermostat is in it? and does it have the balker plate on the end? Your car has a large bypass system and if it is not fully closed off when the thermostat is fully open you can see high temps. There are thermostats that fit but are not correct. Even the aftermarket manufactures can get it wrong.

With your history of high engine temps you should pull the thermostat, read the temp rating on the thermostat then put a pan of water on a stove and put a meat thermometer in the water and watch at what temp it starts to open and at what temp it is fully open then measure the distance from the flange to the balker plate. Then measure the distance on the housing to confirm that the balker plate dose hit and close off the port in the thermostat housing.

ONLY then do you know for sure that it is doing it's job.

Next, get the dye from any auto parts store for the radiator to test for CO. This is a test to see if your head gasket is leaking any combustion into a cooling jacket. You already know that oil is leaking from the pushrod space out of the engine so it is quite possible that there is also combustion leaking also and into a coolant jacket.

Your car with an alloy radiator and an electric fan should run cooler then a new factory car.

let me know,


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Howard M. Fitzcharles III


Triumph TR-4 up & Spitfire, and Engine theory


Dealership line mechanic on MG, Triumph, Jaguar for 15 years, Instructor in commercial mechanics school 2 yr. Product information manager for piston and valve manufacture, Instructor & hotline answer man for import car parts importer 15 yrs.

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ASE Master Auto with L-1 certification up to 2000

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