Hey guys, so I recently bought a montero sport, 2003, LS, 3.0L (6G72). I've noticed my rad coolant is all gunked up, and it's coming out of a hole in the overflow inlet in the plastic all over the right side of the engine bay. Now, the colour of it is orange, and I believe it's the crappy orange canadian tire coolant, but I can visibly see small amounts of oil floating In my reservoir, and i believe that's why its gunking up. I've checked both my engine and tranny oils, and both seem to be just fine and uncontaminated, but the rad coolant definitely smells of tranny fluid.

I'm wondering if theirs at any point in either system, they may intersect, or come close, whether it be gasket, cooler, heater core, lines, etc. I'm doing a coolant flush tomorrow and I'm going to drive It around for a week or more to see how long it takes to get to this point to determine how bad the leak is, but I'd like to get an idea of where it's most likely leaking from.

 

What colour and condition is your transmission fluid in?

 

Tranny fluid is red, seems fine, at least it is on the dipstick.

 

That is a good sign. If trans fluid was getting in to the coolant, it would also have water in the transmission, which would send trans oil pink and milky
There are products on the market that you can add to your cooling system that help with the flushing, and break down the oily components.

 

What could the oil be from then? My trans oil is fine, as is my engine oil, the previous owner had stated it had a new radiator in it, so I can only assume he's had this issue before..

 

Cross contamination between different types of coolant can cause gunk to collect. Im not sure of your locale, but it is best to use the manufacture recommended coolant your vehicle takes. Here in Australia vehicles can suffer with incorrect spec coolant causing issues. Also coolant ratio to water is important. Too much concentrated coolant and not enough water can cause as many problems.

you idea of changing the coolant and trying it for a week or so, sounds sensible.

 

I can't confirm this 100%, but on full size Montero transmission cooler is built into the main radiator. Engine oil cooler is a separate stand alone radiator. It's possible to have transmission fluid and coolant mix if there is a pinhole inside of the trans cooler. If that is the case, you need to address it right away, or you risk ruining your transmission. First, confirm that the contamination is not coming from engine oil/combustion chamber. There are inexpensive kits available to test for that. One thing you can do is to take radiator to a shop where they can pressure test both compartments. Once radiator is repaired, you probably should change both fluids.

 

[QUOTE=Artskye;331291]Hey guys, so I recently bought a montero sport, 2003, LS, 3.0L (6G72). I've noticed my rad coolant is all gunked up, and it's coming out of a hole in the overflow inlet in the plastic all over the right side of the engine bay. Now, the colour of it is orange, and I believe it's the crappy orange canadian tire coolant, but I can visibly see small amounts of oil floating In my reservoir, and i believe that's why its gunking up. I've checked both my engine and tranny oils, and both seem to be just fine and uncontaminated, but the rad coolant definitely smells of tranny fluid.

I'm wondering if theirs at any point in either system, they may intersect, or come close, whether it be gasket, cooler, heater core, lines, etc. I'm doing a coolant flush tomorrow and I'm going to drive It around for a week or more to see how long it takes to get to this point to determine how bad the leak is, but I'd like to get an idea of where it's most likely leaking from.[ if you have tranny fluid in your radiator you have already destroyed your automatic transmission that's 100% guaranteed I've seen it a dozen times I'm sorry to have to tell you the bad news your radiator is cracked on the inside and your transmission is toas

 

[QUOTE=Artskye;331291]Hey guys, so I recently bought a montero sport, 2003, LS, 3.0L (6G72). I've noticed my rad coolant is all gunked up, and it's coming out of a hole in the overflow inlet in the plastic all over the right side of the engine bay. Now, the colour of it is orange, and I believe it's the crappy orange canadian tire coolant, but I can visibly see small amounts of oil floating In my reservoir, and i believe that's why its gunking up. I've checked both my engine and tranny oils, and both seem to be just fine and uncontaminated, but the rad coolant definitely smells of tranny fluid.

I'm wondering if theirs at any point in either system, they may intersect, or come close, whether it be gasket, cooler, heater core, lines, etc. I'm doing a coolant flush tomorrow and I'm going to drive It around for a week or more to see how long it takes to get to this point to determine how bad the leak is, but I'd like to get an idea of where it's most likely leaking from.[ if you have tranny fluid in your radiator you have already ⁸destroyed your automatic transmission that's 100% guaranteed I've seen it a dozen times I'm sorry to have to tell you the bad news your radiator is cracked on the inside and your transmission is toas

 

Alright update guys, so about 12 days ago I dropped my truck off to a shop for a coolant flush and pressure test after what I thought was coolant on the underside of my truck. They flushed the old stuff out (orange/brown/beige) and refilled with OEM coolant which was blue. The pressure test came back as no leaks, and they sent me on my way. Today, just 12 days later, the coolant has gone back to the same old colour. It has a relatively new radiator, and the tranny cooler is separate, so the only way fluid could intersect, is somewhere further down the line, which I could not see. Otherwise, my engine oil is black, no contamination, it is leaking on the valve cover as well. Is there any kits that I can buy that will tell me exactly what the coolant is made up of? Whether it be oil, rust, etc.? I dont really want to rip everything out and physically look at the gasket if I dont 100% know it's bad considering I've never done any mechanics that in depth. Thanks guys.