V1 Coolant leak between engine and trans!?!?

[PHENDERSON]

LSJ...coolant dripping from between the engine and trans, where the large metal "gasket" sits between them. Very slow when the engine is off and a good leak when running.

I may have done something stupid when trying to completely fill the system with coolant. I noticed the return side hoses were fairly empty so I poured coolant into the hose to fill it up...then also straight into the engine where the hose connects. I figured thats where the coolant enters the engine. Maybe it's over filled and leaking until its not. Maybe something else?

Any ideas?

 

[Ross]

My first guess was the coolant bottle overflow hose... but my Goblin doesn't have an overflow hose.
Is it engine coolant or intercooler coolant? Do you have the 2 systems different colors?
There is no gasket line between these 2 coolant systems and the clutch bell housing. A rear main seal failure would let engine oil in.
So no idea how you accomplished this leak.... need to investigate further.

Check above the transmission... maybe it is from the thermostat housing? Loose hose clamp? Leaky hose?

 

[PHENDERSON]

I have looked everywhere and can actually see it slowly seep through the crack between the engine and the metal plate separating the engine and trans.

First time I started it I had 2 bad oil leaks but replaced the head gasket and fixed those.

Then after the first drive I had a small oil leak under the trans...I put in a new rear main seal when i rebuilt the engine so maybe it just needs to seal better. Then I filled the return side with coolant and now it's leaking coolant between the engine and trans...it never leaked coolant prior to filling it there. I think the oil leak is gone but not positive. I'm going to let it idle for a while and probably drive it around the block and see what happens. I almost hope it just blows up and then I can beg the wife for a new complete block.

 

[Ghostknife]

Could it be from your Laminova Core cover? Maybe some pictures would help. I used 2 different colors for the two different systems to help in finding leaks

 

[PHENDERSON]

I do keep topping off the HX loop and can't find a leak anywhere. Maybe it's that loop not the engine coolant.

Good idea, I'll have to drain 1 and use a different color. If it wasn't so loud (different discussion) I would let it run for a while and figure it out maybe.

 

[Gtstorey]

You can also get a radiator pressure test kit for not that much money and leak test the systems.

 

[jamesm]

Check the old heater core hoses, the thermostat housing, and the oil cooler lines. They all sit right above where the engine and trans meet and may be leaking.

 

[jaredthenav]

I recently had a leak on my heater hose loop, and it was dripping right around the rear transmission mount. I had used an old hose from the Cobalt to close the loop and it had degraded too much. So new hose, new clamps, and no more issue.

 

[PHENDERSON]

Thanks for the ideas

 

[Sluggonaut]

My coolant leak was due to an older hose and the spring clamp at the thermostat. It ran down the exact spot you mentioned.

 

[snirtman]

Tom Anderson posted a YouTube video of a similar leak he had. He speculated it was freeze plug(s). He also had an LNF, so maybe totally different for LSJ.

Edit: He posted a later video claiming his mechanic diagnosed it as a cracked block. Yikes. Hopefully an LNF block defect.

 

[PHENDERSON]

Oh boy...haven't even considered a cracked block. Short of removing the engine and taking it apart how would one diagnose that as the culprit?

 

[Gtstorey]

This is where the coolant pressure testing can come in handy. You say that you have a pretty good leak when running. You can pressurized the system when everything is cool and can access safely. Of course if the leak is between the transmission and block it will be hard to know exactly what is going on. You could also try fluorescent dye. I think they make some for cooling systems but I've never tried them.

 

[PHENDERSON]

Back at it again! Got my AEM wideband and aftermarket fuel gauge working so I topped off the coolant and started it up and wouldn't you know, it's pissing coolant at the very bottom of the engine again. Right where the trans meets the engine. I looked and don't see it leaking down from somewhere up higher. The coolant coming out is clean and the engine oil appears to be clean so I don't think there's any mixing of the 2. Is there anything under the bell housing that would leak coolant? Oh, the exhaust is normal, no thick white smoke. I feel like I'm just chasing problems with this thing...going on 2 years now and I still haven't been able to drive it. How frustrating.

 

[Ross]

The water jacket only goes to the block, the head, and the side casting that has the water pump. There is no coolant in the bottom 3.5" cradle/girdle casting below the block, or the oil pan.
Is the thermostat area leaking water into the bell housing? That area has a lot of hoses connecting.

 

[PHENDERSON]

Maybe I need to look harder. The leak is fast so it should be easy to spot if it's something on the outside. I hope it's something easy.

 

[Gtstorey]

Make sure it isn’t brake fluid from throw out bearing.

 

[PHENDERSON]

Definitely coolant. It's the orange premix dextron stuff and I can see the level in the overflow tank drop as it drains out the engine. It's not a drip, it's a constant stream. It takes about 30 seconds to drain the overflow tank. With something leaking that much you'd think it would be easy to spot.

 

[PHENDERSON]

Maybe I'll just put a 50 gallon expansion or overflow tank (which ever it's called) and that'll last me for a 30 min drive

 

[ah.b.normal]

I believe the UV dye w/ Black light and glasses is your best bet. Goblin's are usually built from wrecked cars. Did you ever have the Trans off? How long has this engine been running? Is it possible that the engine was damaged in a prior wreck? It is possible "something"(a bolt or nut) got wedged between the flywheel and the block and knocked a hole in the water jacket. I don't think there are any freeze plugs on the back of the ECO-TEC. (I'll have to look in to that possibility.) I once got a deal on a used LS, allegedly "locked up". First they thought "bad starter" and put one on. It still would not turn over! The motor was pulled out and returned as a core. Upon disassembly I found one of the torque converter bolts between the flywheel and the back of the block that would not allow the engine to turn! Paid $75.00. My lucky Day! So, stranger things have happened. It would really be nice if it is the thermostat area leaking! Much easier fixes.