Transmission fluid in radiator

Someone please tell me what's going on! !!!?!

Transmission cooler is leaking. Radiator shop can fix.

Radiator?

Radiator?
What the hell....why not help the poor guy lol

I'm hoping it's transmission fluid! Smells like it, no water in oil, no water in transmission fluid,water in heat exchanger has a brownish, yellowish gunk in it. Engine runs smoothly, no smoke, not idling rough, no noticeable leaks around the engine, your comment makes sense. I'm grasping for straws, looking for reassurance that it isn't a blown engine.

Trying to rule out blown head gasket, is there a way to tell if it's oil or transmission fluid?

What make and model of engine? Does it have an engine oil cooler in the fresh water loop?

Ted

It's a 5 cylinder 70 hp '84 Pathfinder with 3500 hrs on it. It has a transmission oil cooler in the fresh water loop.

I'm hoping the problem is the transmission cooler is leaking into the heat exchanger

Pictures of what you are talking about.

After rereading this thread, I have no clue what you are trying to describe.

If tranny cooler is on FW loop, it certainly can put tranny fluid into the coolant. What kind of tranny? Post a few photos of the rig.

Some tranny coolers are pressurized with fluid, some are not. Thus the question.

This is an SUV (car), isn't it?

Ted

That pretty much sums it up!!! I'm trying to figure out what is causing the brownish, yellowish gunk that smells like transmission fluid in the heat exchanger. The fact is that the heat exchanger cools the transmission fluid so somewhere during that cooling process transmission oil is getting in the water of the heat exchanger.

It's a diesel engine in a trawler

Cars with automatic transmissions have a tube going thru one of the radiator tanks that cools trans fluid or warms it in cold weather. It's somewhat common the have the tube fail from corrosion/rust. If it's an '84 radiator, the better fix is a new radiator. If too much water gets into the trans, lack of proper lubrication will ruin the trans.

From what you're saying, it's most likely the internal transmission cooling circuit in your heat exchanger has developed a leak.

Just bought the boat, don't know when coolant was changed, all of you have made some good points, thanks so much. Now i have some direction to go in besides the battered mutterings of my mind! I will keep you posted. Let's call it a day and have a tall cool something or other! Thanks again, I am feeling like the signs aren't pointing to a blown engine!

If you take a sample of the contaminated coolant you could bring it to a place that does oil analysis they could tell just what kind of oil/ fluid it is. The local caterpillar dealer can tell you where to have it tested. That way you can know where to look for a leak.
Good luck!

We've arranged for a diesel mechanic to come out tomorrow, great suggestion! I will keep you posted, until then I'm going to go play some trani / heat exchanger/blown head gasket blues on my saxophone!

Sure sounds like a heat exchanger leak.

Just had a heat exchanger leak on my Perkins. Should be an easy fix. The end cap gasket on the heat exchanger was leaking raw water into the coolant tank. To be more accurate there was not a gasket on the end cap. Just some plumbers putty or goop to seal it.
Don't know if it was a quick fix by the PO or ??? I'll also be rebuilding the other engine's heat exchanger as well with the proper gaskets from TAD.

Hope your issue is an easy fix.

Put down the sax, stay beside the mechanic and watch what he does. Crack on your a bit simple and ask him politely to explain how he is diagnosing the fault.
Because the boat/engine set up will be new to him he will check each circuit and by a process of elimination isolate and identify the fault, watch,listen and learn to help build up your own knowledge.
The reference in an earlier post to radiators is because a radiator repair shop can also fix heat exchangers too.

Transmission fluid heat exchangers are pretty cheap. Many consider them throw items as the cost to repair exceeds buying new. What dimensions and shape is your transmission heat exchanger? I couldn't quite make it out in the attachment.

I'd just change trans fluid and freshwater coolant and monitor them. You can also pressure test the fresh water system for leak down. Then you'd know there is a leak. The only place that I can see for mixing of fluids is in the trans cooler,

Really appreciate the input I'm getting from so many on the trawler forum. Based on your input I've come up with a game plan... 1. Get the oil analyzed, 2. I am expecting (and hoping)that it is trani oil, if that's the case I will replace the heat exchanger and the oil cooler, then 3. flush the cooling system. So far not a major problem, if it's engine oil in the water....well that's a different beast! Thanks again for the advice, I will keep you posted.

Do you have an 'oil absorbent sheet'. Specifically the type that ONLY absorb petroleum? If so tear/cut a couple inch long strip. Dip it into the radiator. (Don't drop it it1). Let it sit there for a while. When you remove it if there's ANYthing on it then you have: 1. Crank case oil (head gasket block or liners cracked). 2. Bad tranny cooler.

For there to be petroleum IN the coolant it has to be coming from somewhere.

Are oil levels in block or tranny dropping? If the oil level's changing that's where the source is.

What a difference a day makes! Put a sample of the liquid and gunk from the radiator into a mason jar and went to the best diesel people around, walked into his shop and said I need a oil analysis on this, he took it from me, leaned back in his chair, smiled and asked me why and I proceeded to tell him, he interrupted me and said, "there's no oil in that" I asked him how he could tell and he said "it's it's a glass container and there is no oil on the glass, he said all it is is coolant that hadn't been changed in a long time. Asked where the boat came from I told him Washington and also Alaska. He went on to tell me that up there they put all kinds if fluid in the coolant, just flush the heat exchanger out several times and everything gonna be alright. A good example of plain ol common sense, an in the field oil analysing test! Tom Petty said it best "most things we worry about don't happen anyway!" Gonna sleep good tonite! Thanks to all who participated in helping me out, it's appreciated.

Best flush is with 2 part cleaners.

Ain't that good news! But, keep an eye on it for a while just to be safe!

Congrats on finding your issue.

I'm using this Hammerhead Marine Descaler – Bright Bay Products to flush mine.