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TR2/3/3A More TR3 Rear main seal problems. Please Help!!


Freshman Member
I read Tinman58's thread. I just started my rebuilt engine with the machined seal and it leaks pretty drastically.
It seems I have another issue as well. I placed a small, 4" dia. metal tray to catch the oil so I could tell if it was gearbox or engine oil. It is almost certainly engine oil, BUT there is also antifreeze dripping from the same spot. The antifreeze and oil do not appear to be emulsified. There is no indication on the dip stick or in the radiator that oil/water are mixing. I will drain some oil soon to insure that is not the case. Assuming that it is not, where else might this coolant be coming from? I've looked around very carfully and am pretty sure the coolant is not running along the engine someplace and just dripping off at the lowest point. The plug at the back of the head is NOT leaking. Is there some sort of water passage or freeze plug at the back of the engine behind the flywheel? Back to the first problem: Is there any known way to improve the oil seal once the crank has been machined?
Thanks in advance!


Great Pumpkin - R.I.P


Country flag
The Tony Drews link is definitely a good one. My own suspicion, but my bet is the felt around the rear main is also a probable source of common leaks too for rebuilds.

Welcome to the forum too - and if you haven't yet, join the San Antonio club - good group of people there.



Freshman Member
I've been a member of the local Triumph club for many years but this is the first time I;ll have a running Triumph since joining. I've done a mechanical resurrection on my TR3A which I purchased about 1.5 years ago. It's been off the road for 20 years.

So close.....

Links provided by Randall give me confindence that the oil leaks from the rear main need not be a permanent condition. The info is invaluable!

As to the coolant leak, the block drain and heater valve have been scrutinized as has every known coolant junction on the car. All is dry. I tell you I've gone over everything pretty completely. Nobody hopes more than me it turns out to be something simple. Are there any freeze plugs at the back of the motor other than the one at the back of the head?

One thing's for certain. Someday soon, the motor comes out again. Yippie. At least there is no coolant in the crankcase. I slacken the pan plug to let out a small amount of (mercifully) uncontaminated oil.

Sincere Thanks to all.....


Country flag
Only freeze plug I'm aware of in the back is that one on the back of the head. I know you've checked, but just in case:

Run your finger right at the base of the head at the back, perhaps its a head gasket issue?


Freshman Member
Re:TR3 Rear main seal....The Long and Winding Road

I wanted to take a moment to provide an update for the interest of those that were kind enough to provide advice and for the benefit of the greater good through the miracle of the search function.
The dripping fluid turned out to be fuel, not coolant. How can I mistake fuel for coolant? The fuel was from my first post-rebuild tank of gas and had taken on an orange color from the tank sealing product I had used called RedKote. It turns out that in small quantities this exactly replicates the color of the orange extended life antifreeze I'm using. Fuel color has since returned to a more traditional hue. Apparently my sniffer don't work so good either.....
The rear main seal turned out not to be the source of the oil leak...but I had to pull the engine again anyway. I removed the sheet metal clutch inspection plate which allows an ever so narrow view of the rear main seal area which appeared dry. Convinced that the source of the leak must be the pan gasket I pulled the pan only to notice a bit of that pesky coolant in the crankcase. The engine builder had not sealed the liners properly. Problem fixed, I've reinstalled the engine and the TR3 has ~20 miles on it since. So far, no leaks (!!!). I continue to sort minor issues. Currently awaiting rebuilt temp gauge. I'm close...so close!!!


Luke Skywalker
Country flag
Re:TR3 Rear main seal....The Long and Winding Road

Sounds good, post pix!
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