Coolant Leak at Oil Pan

[f2502011]

96 Bronco 351. Noticed a few drops on the ground. Crawled under it and there was water on the bottom of the crossover pipe. Looks like its coming from the oil pan gasket area in between the two oil pan bolts one is to the front of the dipstick tube and one to the back. Almost comes out of the oil pan gasket right under the dipstick tube. Doesn't appear to be coming from any higher such as the freeze plug above. It doesn't appear to be mixed with anything just straight coolant. The oil also looks good. Runs and drives fine otherwise. Any ideas?

[jermil01]

could be the gasket between the water pump and the timing cover.

[JBfab]

Sound like maybe just maybe you have a leaking oil cooler if your truck is equiped with one. Its between the block and oil filter. If thats not the case try one of those uv additives. Add it to your coolant run it awile and then turn on the special light, Or a black light.

[mnlabgeek]

The uv light would be a great help.
I just traced a coolant leak on my 351. It started at the upper intake in the front, pooled by the timing cover, leaked down to the oil pan gasket, traveled down the oil pan to the rear of the oil pan and dripped down the bellhousing. Most confusing part, no leaks on the ground and no visible traces except under the bellhousing. I had to remove the upper intake to trace the leak. Long story short, clean it up and trace it to the source. The uv additive can make the job easier and quicker.

[f2502011]

I just crawled underneath and had a look at the front of the motor. The leak appears to originate at a bolt at the bottom backside driver side of the water pump. Coolant then appears to run down to the oil cooler and also along the oil pan where it collects and then drips on the ground. How should I approach to fix?

[jermil01]

If you're certain that is the origin of the leak and it's not coming from somewhere higher up, then my bet is on the gasket. Anyway, you're going to need to pull the water pump and replace the gasket. depending on the age of the pump you may want to replace that as well.

[Alvin in AZ]

Cool thread! :)

I have three factory-built 351w/5.8's and all three of them
leak a little bit of coolant at the lower intake manifold. :/

What's up with that?
Is it a common thing?
I got the only three in existence that did that?

Pools up near the top of the water pump/timing chain cover.

"fixed" one, but not so sure I didn't actually make it worse! :/

I used Ultra Black but next time I'll try "Right Stuff".

Alvin in AZ

[f2502011]

Originally Posted by jermil01

If you're certain that is the origin of the leak and it's not coming from somewhere higher up, then my bet is on the gasket. Anyway, you're going to need to pull the water pump and replace the gasket. depending on the age of the pump you may want to replace that as well.

No evidence of anything higher but it may be different once I dig in. The pump is the original one.

[jermil01]

Can you tell if anything is coming from the weep hole of the pump..it would look like this..

[f2502011]

Originally Posted by jermil01

Can you tell if anything is coming from the weep hole of the pump..it would look like this..

Yes I saw that too. A little of moisture on it but not as much as in the picture. I think it's been doing it for a while. I checked the coolant before we had a cold spell and it was low. I flushed the coolant out and put in all new. Since then it has been more noticeable of a leak. Have read some information on the web indicating that a lot of new engines from the factory contain stop leak and that when the coolant is changed out the stop leak should also be replaced. I didn't do this and am wondering if that might be the issue and possibly the solution. I also saw on the web that GM even sells the little brown discs to put in the system when this is done to stop small leaks. See here http://www.parts123.com/parts123/yb....0h~Z5Z5Z5HAWMC.

I'm thinking about doing this as well. Some say don't use it, it will stop up the system (although i think they are mostly referring to the old style stop leak that is thick and brown and some with pellets) then others have used it with success aftermarket and also new car manufacturers placing pellets in them upon assembly. What are the thoughts here?

[jermil01]

Never heard of stop leak being used from the factory..wouldn't make sense..an engine shouldn't leak coolant period, unless there is an issue with a gasket, hose, or something isn't tight enough. I say not to the stop leak. You'll probably find one of the gaskets on your waterpump is toast.

[f2502011]

Originally Posted by jermil01

Never heard of stop leak being used from the factory..wouldn't make sense..an engine shouldn't leak coolant period, unless there is an issue with a gasket, hose, or something isn't tight enough. I say not to the stop leak. You'll probably find one of the gaskets on your waterpump is toast.

Could be. A general google search turns up a ton of info on stop leak used at the factory and afterwards

https://www.google.com/search?q=fact...&client=safari

Not just GM either
https://www.google.com/search?hl=en&....1.0C2DF7GJSZA

[jermil01]

sounds like they're more intended for aluminum engines, but whatever floats your boat. Give it a try and let us know what happens.

[f2502011]

The back of the water pump is where the leak is coming from. Bottom bolt on backing plate drivers side. The weep hole is dry and there are no traces of liquid coming from it. It also doesn't make any noise or have any play so I decided to try the stop leak. I don't like the idea of putting anything in the radiator other than liquids so I got a small bottle of Bars with the pellets and water pump lubricant. I poured the liquid part into the recovery tank then put in about a tablespoon of the pellets. I figured the small size of the overflow hose would act as a filter for pellets/solids, but that the pellets when mixed with warm coolant will dissolve and continue to provide protection and prevention of leaks over time. I've driven it around a couple days now and everything is dry (knock on wood). I'll post up if any issues with it happen in the future but hopefully won't have to.

[DABUCKIN]

It started at the weep hole for me and ended up like this....

[f2502011]

Originally Posted by DABUCKIN

It started at the weep hole for me and ended up like this....

Please elaborate I'm not sure what I am looking at.

[DABUCKIN]

Originally Posted by f2502011

Please elaborate I'm not sure what I am looking at.

Timing case cover, to which the water pump is attached to. The water pump started to leak at the weep hole. I quickly found out that WP was frozen and I had to replace alot of parts.

[Alvin in AZ]

Originally Posted by f2502011

The back of the water pump is where the leak is coming from. Bottom bolt
on backing plate drivers side. The weep hole is dry and there are no traces
of liquid coming from it. >snip< I've driven it around a couple days now and
everything is dry (knock on wood). I'll post up if any issues with it happen
in the future but hopefully won't have to.

Cool, thanks for the report. :)

BTW, all those bolt holes are "blind holes" (they don't go through into the
water jacket) so what you've got is a gasket leak near that bolt, see? :)

Alvin in AZ

[jermil01]

wow..I've never seen a timing cover in that bad a shape before..were you running straight water in that?

f250, hopefully the stop leak will do the trick for you, but I'm betting ultimately that gasket will need to be replaced.

[f2502011]

Originally Posted by jermil01

wow..I've never seen a timing cover in that bad a shape before..were you running straight water in that?

f250, hopefully the stop leak will do the trick for you, but I'm betting ultimately that gasket will need to be replaced.

I hope so and know it will eventually need to be replaced. Hoping this will buy some time and miles.