Ideas for chasing down this coolant leak? - PeachParts Mercedes-Benz Forum

camsna · #1 07-12-2010, 09:09 AM

'82 240d.

So. I had a coolant leak that was clearly coming from the radiator. I replaced it. I also replaced the thermostat and thermostat seal. I also replaced the thermostat gasket and that small 2' long hose on the thermostat housing. All the other hoses look totally fine.

Now there's still a leak. Not NEARLY as bad, but it's there. Here's where it gets a little weird.

It always seems to be way worse when the car is parked on an incline. I drove it pretty hard and stopped on a flat road, two or three drops leaked. I stopped on an inclined road, there's the leak. Stopped in the driveway - same thing.

I'm about out of ideas. Can you help me think?

Thanks!

leathermang · #2 07-12-2010, 09:29 AM

Can you clean the area, cause it to leak again , and take pictures of where you see it ?

vstech · #3 07-12-2010, 09:32 AM

go to an autoparts store, and rent their radiator pump up tester. hook it to your radiator and pump up the coolant system and look for the squirting water...

leathermang · #4 07-12-2010, 09:33 AM

Recipe for getting your shoes wet....

JB3 · #5 07-12-2010, 09:41 AM

Quote:

Originally Posted by vstech

go to an autoparts store, and rent their radiator pump up tester. hook it to your radiator and pump up the coolant system and look for the squirting water...

I second this, if you pressure test the cooling system, you will find where its coming from.

#6 07-12-2010, 10:09 AM

Most any reputable radiator shop will pressure test it for free or a small token fee. Getting a radiator pressure tester on the loaner program from your favorite chain auto supply will also work.

69shovlhed · #7 07-13-2010, 10:50 PM

i'd prefer to do the pressure test cold. hot coolant can really burn you...

camsna · #8 07-13-2010, 10:59 PM

Pressure tested it. Looks like water pump housing. The turd I bought it from said (for what it's worth, I believe him) that he replaced the water pump and radiator one year ago. Three days after I bought it, radiator all but explodes, thermostat housing is leaking, and water pump housing is leaking.

The real rub is that the gasket is an 85 cent part that'll cost 10 bucks to have shipped. Killer.

vstech · #9 07-13-2010, 11:20 PM

... radiator all but explodes, and WP is leaking... what pressure cap is on the car?
you should have the cap tested. it could be holding in excessive pressures, and they found their way out of the system... also you could have a head gasket problem pumping in pressure that the cap vent can't handle.

camsna · #10 07-14-2010, 01:01 AM

Head gasket?! AAAAHHHHHH! I hope that's not it. I've replaced the cap - the old one's seal was cracking. The new one feels a little more 'loose' (which I know is not necessarily an indication of pressure) than the old one did.

And replacing the radiator (seam busted) and the thermostat stopped most of the problem. It seems to me (an ignorant layman) that it was just third rate repair work. The system was full of brown sludge, the radiator was a piece, the thermostat was a cheap-o made-in-China piece of junk, the gasket looked about a hundred years old, etc.

Man I hope it's just this last gasket...

I'm all nervous now.

H-townbenzoboy · #11 07-14-2010, 11:29 AM

Just FYI, if you use the MB coolant or its equivalent, it will leave a powdery residue trail as it dries so you can easily track down leaks.

vstech · #12 07-14-2010, 11:42 AM

Quote:

Originally Posted by camsna

Head gasket?! AAAAHHHHHH! I hope that's not it. I've replaced the cap - the old one's seal was cracking. The new one feels a little more 'loose' (which I know is not necessarily an indication of pressure) than the old one did.

And replacing the radiator (seam busted) and the thermostat stopped most of the problem. It seems to me (an ignorant layman) that it was just third rate repair work. The system was full of brown sludge, the radiator was a piece, the thermostat was a cheap-o made-in-China piece of junk, the gasket looked about a hundred years old, etc.

Man I hope it's just this last gasket...

I'm all nervous now.

brown sludge from a system with a new waterpump and radiator???
forget third rate, this sounds like 4th rate or worse! if you're gonna pull the water pump AND the radiator, uh, flushing the block is only a coupple more steps. putting in antifreeze is a no brainer too. I hope this guy didn't try a citric flush and leave it in there!!!

kerry · #13 07-14-2010, 12:11 PM

Are you sure it's not the water pump itself that's leaking? Coolant coming out of the weep hole will often run over to the housing and look like a housing leak to the untrained eye.

camsna · #14 07-14-2010, 01:16 PM

Quote:

Originally Posted by vstech

brown sludge from a system with a new waterpump and radiator???
forget third rate, this sounds like 4th rate or worse! if you're gonna pull the water pump AND the radiator, uh, flushing the block is only a coupple more steps. putting in antifreeze is a no brainer too. I hope this guy didn't try a citric flush and leave it in there!!!

That's what I thought! Why not at LEAST run a hose through the block? It's beyond me.

camsna · #15 07-14-2010, 01:18 PM

Quote:

Originally Posted by kerry

Are you sure it's not the water pump itself that's leaking? Coolant coming out of the weep hole will often run over to the housing and look like a housing leak to the untrained eye.

I'm not sure. How would I know? I know you're sure you said it obviously - and I'm totally sure you did - but I'm pretty thick, so an overly-detailed description, if you're willing to give one, would be really helpful!

Thanks, fellas!