Hi All!

I'm having one strange little coolant leak. First off, what I've done!
The van is a 1989 B250, 5.9L 360 engine in spectacular health given it's previous owner abuse.
I've replaced all cooling hoses. Heater, lower, upper, and bypass. I also did a check to ensure that the hoses are connected good and that the clamps are on tight. This mysterious leak certainly isn't on any of the hoses.

What I know so far: The leak only occurs when under pressure. Found this out by doing a pressure test on the system. It's also an external leak, too. The oil's nice and clean, no foaming or any leaks into it. I also did a quick visual and I couldn't find any leaks near the input hoses on the water pump, but since I haven't taken apart anything I wasn't able to get an excellent look at the back of the pump.

The leak appears to be happening in the front of the engine, not near the radiator, and looks to be pooling/dripping down to the oil pan. I'm inclined to say it's a leaky gasket on the water pump. Who only knows when the last time that thing was changed! But I'd like to get another opinion.

I'm going to be doing a front-end teardown in two weeks, but I'd much rather have the parts for repair in hand before I tear it down, and spend the time doing repairs rather than diagnosis!

Thanks all!

Attached picture is oriented as such: Front of engine is to the left.

 

There is a weep hole on the bottom of the water pump, when it starts leaking it means the clock has been ticking. Also many of the bolts which hold the waterpump and timing chain cover to the block penetrate the water jacket and can weep coolant.

Consider doing the timing chain at the same time as the water pump. Timing chain kit and new water pump can be had for about 85$, timing chain cover gasket kit with repair sleeve for harmonic balancer about 20$ more.

Ir you are doing a full tear down make sure you know which bolts came out of which holes, and where the spacers go and the order or removal and locations of the accessory brackets. Reinstall the long bolts with rtv to seal them in the block.

Check the freeze plugs in the block too.



You do not need to remove the oil pan, but you will get coolant in the oil pan if you remove the timing cover, so get new oil and a filter, and 4 gallons of 50/50 coolant, or 2 gallons undiluted and 2 gallons distilled water. Do not use tap water. Might as well do the thermostat too, and if you want to really go nuts, flush the cooling system while waiting on parts with a radiator flush type product.

You can flush and back flush the heater core too while you're there.


Look at how much work I just made for you

 

Hooooo boy.
I was afraid that I had my work cut out for me....but you're right. If I'm going to go in there, might as well give it as much of a spruce-up as I can!

The nice news is that I've all ready done a flush and replaced the old thermostat. Bloody thing was rusted to hell and gone (which is what caused me to do the flush in the first place). So that's two less things on the bucket list o' repairs!

Thanks loads Landyacht! Now I have some peace of mind...and a little less money in the wallet (surprise!). Time to order up some parts!
I'll post back with how the repairs went in aboot two weeks or so.

Have to say....these forums rock! Hopefully I can help someone out eventually with what I've learned so far. :P

 

What I use to find hard to find leaks is a UV dye and a black light, it makes things so easy to see. I have a kit i got online for all the fluids and have used the hell out of it. here is a link to show ya what i got. http://www.autoservicesupply.com/Mas...-Detector-Kits
you might just be able to find some UV/Black light dye at a parts store and a cheap light. run the car for a while to get thijngs mixed up and that new thermostat a chance to open, let it cool down enough to take off the rad cap, hook up a pressure tester and start looking.

 

Also not a bad idea!
We've got blacklights hanging out up the **** in the garage, so that's not an issue. Might as well do that test before hand so I can see if it's leaking from anywhere else.

Oi....I always wanted to do a restoration project on a vehicle...looks like I'm finally getting that chance.

Thanks Neutral!

 

Also the first time i used the dye i had the lights on in the shop, couldn't really see anything. then the wife comes in and I was saying I couldn't find the leak. Like always she thinks outside the box and flipped the lights off and BAM! saw it glowing really easy.