I need help to I.D. this weird leak.

[Erik Jenkinson]

I woke up this morning to find a puddle of very clear (Yellowish) fluid under my m1009. Judging by its color, it seems like unused motor oil. As I looked closer, I began to think maybe I had a leaky brake line, but dont see any obvoius leaks thereabouts. As I looked for the source, I thought it may be a fuel line or the IP, but I dont see any fuel in the valley under my intake. This leak apperars to be coming from the small mounting plate where my engine temp sensor is, as well as the similar small plate on the other side. What strikes me a odd is that this fluid is very clean, while the oil in my crankcase is about as dark as one would suspect. Not cloudy or burnt. No oil in my radiator. The truck behaves pretty normal, no smoke etc. I very recently replaced the rear main and oil pump, maybe 600 miles ago. That little mounting plate was maybe ever so slightly loose, but this leak continues even as the vehicle just sits. It isnt coolant. I dont see a brake line in this area. Anyone ever see this before?

 

[firefox]

Just a guess, but you might check your steering gear pump oil and see if it is the same
color and consistancy.

 

[Warthog]

What is the texture? Oily? watery? Any smell? Did you do a taste test?

From the location of the leaks, my guess is coolant.

 

[steelandcanvas]

Maybe where the Cat peed?

 

[Westech]

Fuel

 

[Erik Jenkinson]

The cat pee tasted the same as whats in my radiator. I fired it up to see if I might find the leak at pressure. I think Ive blown a head gasket (or both) just a very slight bubble right at the back of the head. I don't see anything in my oil or radiator. Ive never done a head gasket before. It looks involved. Then again, so did the rear main, but I pulled that off after many curse words. Im somewhat inexperienced, but really enjoy working on and driving this thing. Should I go for it and replace the head gaskets? Any advice would be appreciated. Ill be reading the TMs all night (AGAIN). How difficult is this?

 

[Warthog]

Replacing the head gaskets isn't that bad. Do use new head bolts as they are a one time use item.

 

[Erik Jenkinson]

Ive been doing some reading, and it seems as though a blown head gasket is more likely to blow out internally, mixing oil and coolant or vice versa. I dont see any evidence of that. Is it uncommon for a head gasket to blow out where the coolant is able to escape the head, rather than leaking inside?

 

[zout]

Erik - you could try pressure testing the radiator to see if coolant (guessing its still coolant at this point) to see if you could force any out under a slight higher pressure than the radiator cap pressure and less than to blow your hoses off.

 

[Stonepicker1]

I thought I had a blown head gasket on my M1028, but turned out it was leaking coolant from that same little mounting plate. If I was you, I would pull that plate off, look at it real close. If all is good, I would re-gasket it and install it back on. Doing a head gasket is a "pain in the back" when the engine is still in the truck. Do the easy fix first.

 

[Triple C]

You aren't driving this vehicle right? Someone help me out here but as I understand it, if you have a high pressure coolant leak it will cut the deck of the head pretty quick - or can. As I understand it, IF it is a blown head gasket, driving it could be the difference between replacing the gasket and having to mill the heads or block. An abundance of caution would dictate not driving it until the problem was corrected - I think.

 

[Stonepicker1]

I'm 90% sure it not a head gasket leak from his first pictures and saying the rear block-off plates is were the fluid was leaking. All he has to do is remove the two bolts on each plate, clean off the old gasket(red RTV) and install new gaskets with a little RTV and let it sit overnight. That should fix his leak.

 

[Triple C]

Sounds good Stonepicker1, I hope that is all it is. Should he drain off coolant before he takes those plates off or is it not necessary?

 

[Stonepicker1]

Sounds good Stonepicker1, I hope that is all it is. Should he drain off coolant before he takes those plates off or is it not necessary?

He should be ok as long as the engine is cold.

 

[doghead]

What block off plate are you talking about?

 

[Stonepicker1]

What block off plate are you talking about?

like the ones I have the green tape on.

 

[doghead]

Ah!

Thanks.

 

[Erik Jenkinson]

I found it. I just got home and everything had dried up, so I knew for sure it was coolant. I cleaned all the suspect areas and let it idle. It took awhile, but sure enough, right at that little plate containing the temp sensor I saw steam rising. The fluid is coming from there. That being said, I noticed these conditions, and wanted to make sure they are "normal"
1) My passenger side of my radiator was far hotter than the drivers side. (I think that may make sense)
2) I noticed that my crossover pipe was really hot, but the thermostat hadn't opened yet. I put a new hockey puck one in from NAPA awhile back. If the thermostat should begin to fail, does this somehow cause leaks elsewhere? The leak was at the sensor on the drivers side, but I plan to go ahead and re-seal them both while its drained. I did notice though that the big radiator hose by the thermostat did warm up even after I had shut off the vehicle. I believe it still may function. That crossover pipe seemed pretty hot after having idled for about 15 minutes.

Anyway, stonepicker1, you nailed it. I was so sweating the whole head gasket thing, yet am somehow disappointed I wont be learning to do it right now. I think I might have issues. I'll post after I fix the leak. Thank You all.

 

[FMJ]

Doing a head gasket is a "pain in the back" when the engine is still in the truck. Do the easy fix first.

I was thinking of pain in another area. . .

 

[Stonepicker1]

I was thinking of pain in another area. . .

LOL. that to.

That is why I just pull the engine.