Sealing a coolant leak

dragoon

dragoon

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Hi,
recently I've had a coolant leak on one of my engines (Volvo TAMD 40s). I tracked it down to a leaking pipe that goes between the block and head at the very back of the engine.

This pipe is flanged at one end (sealing with a gasket and bolts), and seals at the other with an o-ring (parallel push fit joint).

The end that was leaking has the o-ring. I removed the pipe, cleaned everything up, sourced a new o-ring and refitted (with a little instant gasket).

I then refilled the cooling system (which takes an expensive amount of anti-freeze) only to discover to my horror it still leaks - though not quite as bad as before!

I plan to drain the engine again (pumping the coolant away so I can reuse it).

Does anyone have any thoughts on establishing a good seal? Any recommended product? The surfaces of the pipe and the hole in the block were quite good, but the fit is fairly loose.

Cheers,
Paul
 
I fixed a leak a bit like that on a car engine with Sikaflex. It does mean however it's on for good. Don't know anything about your particular engine but O rings do come in many sizes, cleaning seating faces is obviously important.
 
[ QUOTE ]
... ... but the fit is fairly loose.

[/ QUOTE ]
Can't really envisage how it goes together but could you fit a thicker O-ring for a tighter fit?
 
[ QUOTE ]
The surfaces of the pipe and the hole in the block were quite good,

[/ QUOTE ] But maybe not quite good enough!

You dont say if the new O ring was an "Official" spare or just one you were able to find.
It might be worth trying to find one of a slightly thicker crossection. Metric and imperial sizes are available although the imperial sizes are often expressed in mm. The problem might be due to the difference between the two.
 
If this is anything like the small VP engines (VP2003) than the ring you describe should not be a O-ring but a sort of very short cylindrical shape. It's very important you use the original Volvo parts here as everything else will leak.

Cheers,

Arno
 
Oh god, really, sorry for being a sarcastic twat BUT those things were for real emergencies back in the 60s, i learned as the years advanced, do it properly once and then everything is dependable>
Stu
 
Take no notice of the bodgers, (ive done enough of that in my time by the way!) the only cure is to get the proper part, something as critical as the engine coolant and they want to go in to raw eggs, radweld, gunge!! for fecks sake whats wrong with them!! If you were offshore in a rising gale and you had no choice, bodge away, but as it is now you have all winter to do the job properly.
Stu
 
Thanks to all who replied.

Just to answer some of the questions/comments;

- the o-ring I got was the correct VP part - something silly like 5 pounds for the ring - crazy!

- A replacement pipe is 109 pounds and I'm reluctant to buy one as I'm not sure as it's going to improve things.

- I'd use Radweld (or an egg) in an emergency, but given the cost of these engines when they fail I'd sooner risk creating another problem with a blockage somewhere else in the cooling system.

- I like the idea of using Sikaflex - I actually thought about using some 3M 5200 around the joint to stop the leak, but believe it or not I couldn't find anywhere that has any in stock.

So, I think I'll drain it off, and refix the pipe with Sikaflex. I'm not worried about it being permanent - this engine I stripped and partially rebuilt a couple of years ago and this pipe didn't even have to come out to do that.

Thanks again - this forum is very helpful.

Cheers,
Paul /forums/images/graemlins/smirk.gif
 
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