XM eating coolant

maxwell · Sep 10, 2018

have sort of a strange issue. my Turbo XM was eating coolant all last season. I tore the motor apart after 500km and everything looked perfect so i had no reason to believe it was burning in the engine and the sled ran perfect. if it was using 1 litre a day or more it wouldn't run that good i figured! one day when it was running in the garage i noticed coolant dripping out of the turbo exhuast. it is a liquid cooled turbo so i just assumed it must be leaking out of the center section into the pipe. if it wasnt burnt it wasnt coming from the motor. Now this fall i am tearing the machine completely down for inspection and to try and fix this issue. when i removed the Pipe coolant came pouring out of it. not good. its even sitting in the Y pipe. and i mean a substantial amount. but what i dont get is its clearly not going through the combustion chamber ( head gasket ) because it would be burnt and not visible and the motor would not have lasted 1000km like this with coolant washing the oil off. so my question is where is it coming from? my only thought is that the block is cracked near the exhaust port and its just leaking directly into the pipe?

and yes i drove this sled for 1000km while ingesting coolant haha

NoBrakes! · Sep 10, 2018

maxwell said:
and yes i drove this sled for 1000km while ingesting coolant haha

Gold!

snochuk · Sep 10, 2018

Unfortunately I would say your assumption of a cracked block is correct.

Pretty sure you would know the smell of burning antifreeze.
If it is not burning and just leaking you can just top it up.
But it will not self heal......only leak worse.

maxwell · Sep 10, 2018

snochuk said:
Unfortunately I would say your assumption of a cracked block is correct.

Pretty sure you would know the smell of burning antifreeze.
If it is not burning and just leaking you can just top it up.
But it will not self heal......only leak worse.

ya....its a "remanufactured" one so im sort of leaning the same way.

but if the base gasket was leaking what would happen?

snochuk · Sep 10, 2018

maxwell said:
ya....its a "remanufactured" one so im sort of leaning the same way.

but if the base gasket was leaking what would happen?

You should see antifreeze in there and some would likely get burned coming up through the ports???? Should not be filling pipe from bottom end without burning it.
You would smell it.
Don't think crank would last long with the bottom getting fed antifreeze.

How much antifreeze you loose per ride.

maxwell · Sep 10, 2018

easily a litre and thats not even a full or hard day. i dont run this sled for very long its mainly for racing. it only burns when the turbo and pipe is hot. but still not burning in the engine just burning on the pipe

Frankenytro · Sep 10, 2018

Why not plumb a t into the coolant system with a regulator set at 8/10psi and put shop air at it to see what’s leaking and where it’s going?

Not sure what the cap looks like on the doo’s but you may even be able to just run an adapter from a cooling system kit. Back in the day canadian tire used to loan out tools such as this for free as long as you put down the deposit for the tool, or any reputable mechanic would have the same kit in their box. The t idea is just what I would do in the shop at night if I had to many drinks to be able to get to work and get my kit ha ha ha!

maxwell · Sep 10, 2018

Frankenytro said:
Why not plumb a t into the coolant system with a regulator set at 8/10psi and put shop air at it to see what’s leaking and where it’s going?

Not sure what the cap looks like on the doo’s but you may even be able to just run an adapter from a cooling system kit. Back in the day canadian tire used to loan out tools such as this for free as long as you put down the deposit for the tool, or any reputable mechanic would have the same kit in their box. The t idea is just what I would do in the shop at night if I had to many drinks to be able to get to work and get my kit ha ha ha!

see this is why i posted on here haha!

i have an automotive coolant system pressure test kit. if i hooked it onto the rad cap and pumped it to the rated PSI that should do the same right? may not fit as its automotive but has a couple adapters

Frankenytro · Sep 10, 2018

I have 2 kits, my old Mac one had an inflatable bladder that could seal inside the neck of coolant bottles/resivours so there would be no need for adapters. Other kits you may have to adapt something, but I bet you could even tie into the bleeder screw port (again, not familiar with doo at all... but it could happen with my poos). Sooo many options, but I would totally be starting with a visual inspection with pipe removed. Should be pretty easy to narrow this down in a hurry.

maxwell said:
see this is why i posted on here haha!

i have an automotive coolant system pressure test kit. if i hooked it onto the rad cap and pumped it to the rated PSI that should do the same right? may not fit as its automotive but has a couple adapters

Summitric · Sep 10, 2018

I know someone who probably has a lot of different adaptors

Caper11 · Sep 10, 2018

Your on the right track, try pressurizing the system. If any of your buddies have a borescope they could loan you that may help identify the location of the leak, it may be a head o-ring as well. I know this happened to a BB xp, I cant remember the exact issue with the head but it would eat coolant. He also rode the sled with no problems.

Frankenytro · Sep 10, 2018

If she she is truly eating the coolant in one or both cylinders the piston crowns will be very clean and washed free of carbon in the center. This would also be very easily seen with a borescope.

Caper11 said:
Your on the right track, try pressurizing the system. If any of your buddies have a borescope they could loan you that may help identify the location of the leak, it may be a head o-ring as well. I know this happened to a BB xp, I cant remember the exact issue with the head but it would eat coolant. He also rode the sled with no problems.

tex78 · Sep 13, 2018

It's the turbo leaking coolant and the exhaust pulse back to cylinders is sucking it back into pipe

You would know if it was burning it, smells like burnt doughnuts

team dirt · Sep 17, 2018

A buddy of mines 15 is doing same thing. No turbo though. Been all through the engine now and can’t find a crack. New base gaskets and prints and still leaks. Only smoked on start up after sitting. We think now the water pump is leaking through the shaft into the case.

maxwell · Sep 17, 2018

team dirt said:
A buddy of mines 15 is doing same thing. No turbo though. Been all through the engine now and can’t find a crack. New base gaskets and prints and still leaks. Only smoked on start up after sitting. We think now the water pump is leaking through the shaft into the case.

yikes that's a nasty one.

figured mine out.. hairline crack in th exhast port. would never see it but at 20psi it leak pretty fast! apart she comes. good old cvtech

cattechsummitrider · Sep 17, 2018

team dirt said:
A buddy of mines 15 is doing same thing. No turbo though. Been all through the engine now and can’t find a crack. New base gaskets and prints and still leaks. Only smoked on start up after sitting. We think now the water pump is leaking through the shaft into the case.

That would almost be impossible ( almost ) because there is a coolant leak hole in between the water pump side and the case side, even if the hole was plugged and the the coolant was leaking past 2 sets of seals it would be getting into the oil bath for the waterpump/crankshaft gear and that is sealed off from the cylinders,,,,,

team dirt · Sep 17, 2018

cattechsummitrider said:
That would almost be impossible ( almost ) because there is a coolant leak hole in between the water pump side and the case side, even if the hole was plugged and the the coolant was leaking past 2 sets of seals it would be getting into the oil bath for the waterpump/crankshaft gear and that is sealed off from the cylinders,,,,,

Ya we were thinking it was pretty hard for that to happen but cannot find any other place coolant can be coming out. When we pressure test there is no visible signs of coolant leaking in the top end. It will drain the coolant sitting overnight.

skegpro · Sep 17, 2018

maxwell said:
yikes that's a nasty one.

figured mine out.. hairline crack in th exhast port. would never see it but at 20psi it leak pretty fast! apart she comes. good old cvtech

Got a picture?

cattechsummitrider · Sep 18, 2018

team dirt said:
Ya we were thinking it was pretty hard for that to happen but cannot find any other place coolant can be coming out. When we pressure test there is no visible signs of coolant leaking in the top end. It will drain the coolant sitting overnight.

If you pull the plugs and turn it over does the coolant come out i plug hole or both?

team dirt · Sep 18, 2018

cattechsummitrider said:
If you pull the plugs and turn it over does the coolant come out i plug hole or both?

Engines tore down now but what I remember it was in both holes. Haven’t worked on it since last April but with winter on its way I’m sure it will be back on the books and probably the night before a trip. Might just get a short block as engine has 6000+km anyway

XM eating coolant

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