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Triumph TR6 - To flush - or not to flush?

Following my recent experience with an alloy valve cap disintegration, I would appreciate some opinions on whether flushing the oil is a good idea. The service centre which does our other cars has tried to sell me the idea that it's good and necessary to remove, among other things, oil sludge deposits. I have flatly refused in the past but this situation makes me wonder if it might be a good idea to try to remove the fine bits of debris.

I figure a 'pressure' flush may be the best? but what are the alternatives and the good vs bad.

Roger H

I can't say that I understand an oil flush. The oil in the galleries flows to the main bearings and then runs through the channels cut in the bearings to the hole in the crank journal and out to the crank pin and then sort of "pressed" against the rod bearing. I don't see how any foriegn material would make it past the rod bearing, which typically has around .002" clearance, during a flush. I guess anything smaller than .002 would get through. I suppose you could remove the front most oil gallery plug and flush that out but it still wouldn't address the the galleries that flow to the crank. What is the flush material they use?

Have you dropped the pan yet? You would hope that something from the top of the engine would lay in the bottom of the pan. If it got sucked up by the oil pump then the filter would hopefully catch it before it made it through the galleries.

Not sure that helps you at all...just my thoughts

Good luck
HP Henry Patterson

I'm not too enthused about the flush idea for the engine. See your other thread about a visual inspection. Now if you are running an oil cooler, pulling it and the lines and giving them a good flush might well be in order.

Consumer engine flush that you buy at the auto parts store is little more than kerosene. It does help remove sludge and varnishes but off of surfaces that aren't critical. As Henry says you are not going to get sludge build up on bearing surfaces there is just no room. Now Roger you say that your shop does presure flushes, can't say I've heard of that before.
The only thing that bothers me about it is the definite
possibility of some solvent being left in the engine that would contaminate the next batch of oil that goes in.
Christopher Trace

If you've been using s synthetic oil than I doubt a flush for sludge is necessary.

If you're worried about bits of the aluminum piece - after you've wiped up all traces you find on the head you could pour a qt of fresh oil down around the pushrods. Or maybe the just drained oil (after allowing any particles to settle out) That hopefully would flush out the tappet area and sweep 'em to the crankcase.

The oil would probably sweep most of the particles out the drain hole. Then there is the suction screen and filter to grab the rest. You did drive for a while after the thing fell apart. The best course is to drop & clean the pan and strainer then change the oil filter. Beyond that - why worry?

Brent B

To be honest Chris, I've no details about the process of pressure flushing. It was always on the 'up-sell' notes for the dealer that serviced our Previa. I can't understand why a car serviced from new would need it - I'm sure it involved creating more profit than benefit so I was never interested.

I think pressure flushing involves removing the oil filter and PRV and flushing backwards through the system hence the thought of maybe removing a foreign particle restriction sounds attractive - but I also dislike the idea of anything but oil in there.

Thanks for the reassurance guys - I was thinking along those lines but needed some comfort!!

Roger H

General Motors recently released a bulletin reinforcing GM's position on system-flushing tools, equipment and procedures. "Crankcase flushing is not endorsed or recommended for any GM gasoline or diesel engine. Some aftermarket materials for this purpose may be incompatible with engine components and may damage some engine seals and bearings. Damage of this sort is not covered under the new vehicle warranty"
If you donít have oil leaks now, you will if you flush!!!
Tom Burke


I'd agree with Henry and Steve on this one. I'm in the process of getting a replacement engine with 45K ready to drop in my 6. I'm draining it and dropping the base pan to have a peek and I may run a quart or two thru it as a "flush" but I think my best investment will be the magnetic drain plug from Moss # 328-355 @ $13.95 USD. These are very rugged engines Roger and I doubt you have anything in there that's going to bite you in the long run.

Bob Evans

In older times, before multi-grade detergent oils existed, I found a lot of white sludge in the oil pan and other areas like the inside of the valve cover.

The whole idea of detergent additives is to keep all this in suspension so the pump strainer and/or the filter will trap it while the oil is in motion.

Since doing my engine - along with the total body-off restoration from 1987 to 1990 (about 82,000 miles from 1990 till last August), I used Castrol 10W30 for half this period, then switched to 20W50 Castrol. I have had the oil pan and valve cover off about 3 or 4 times and never had any sludge build-up. I always felt that the detergent properties were doing what they are supposed to be doing. I change the oil and the oil filter every 3000 miles in the engine.

If your engine is this clean, why would anyone need a flush of any kind with an unknown liquid ?

Don Elliott, Original Owner, 1958 TR3A

Don Elliott

This thread was discussed between 15/03/2005 and 27/03/2005

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