Coolant looks like a strawberry milkshake!

[zebra308]

I'm thinking ...this can't be good!

My wife came home today and she noticed there was something leaking under the Denali on the passengers side. When I lifted the hood to investigate I noticed the coolant resevoir was full of a pepto bismal looking foamy liquid. Damn!!!

She then tells me one of the guys at work filled her tranny fluid.... because after she told him it wasn't shifting right...he checked it and discovered it was low. I don't know if he checked it while it was running or not? I don't know if that would make a difference anyway?

I checked the engine oil dipstick/ filler cap and thankfully there's no milky liquid on either ...nor on the tranny dipstick.
At first I'm thinking a blown head gasket? But there aren't any signs of that condition.. truck runs cool despite the foam?
I'm thinking it's the tranny cooler lines in the radiator...maybe one of them is leaking inside the plactic side tank where it goes into the radiator?

Anyone else have this happen or an idea what it could be?

[Springthing]

Hate to ask this kind of question but we're sure the transmission oil didn't get put in the coolant tank, right? This stuff is above my head but I'm sure someone will have some ideas for you soon enough.

[1_low_rider]

I'm thinking it's the tranny cooler lines in the radiator

this would be my first guess, but if im thinking correctly that would mean once the truck is shut off the coolant would be backfeeding back into the transmission as well??? somebody help me out here!! KEEP AN EYE OUT FOR COOLANT GETTING IN THE TRANS, THATS VERY BAD!! and the truck does have to be running to check the trans fluid.

im thinking a new radiator and complete system flush. if i missed anything guys please correct me, im a little fuzzy about the coolant backfeeding issue??

[Mean_Green_95]

Make sure that the guy didn't add tranny fluid to the coolant. Tranny fluid turns to Pepto when water is added to, or vice versa. Just regularly check the engine and trans oil to make sure theres no water in them.

[zebra308]

Thank for all of the quick responses.

I don't think the guy put the tranny fluid in the coolant . There was evidence of him filling the tranny from the tranny dipstick.
I'm really scared that the coolant will flow back into the tranny...that would be bad!!!

I ran the truck for about 1/2 hr. to get it up to temp. No overheating...no steam from the exhaust...no milky colored residue on the oil dipstick or the oil filler cap..so I'm pretty sure there isn't a head gasket problem.
However...the tranny dipstick shows that the tranny fluid is not up to the correct level. now where did it go?
I think into the radiator???

I think I'll need a new radiator and a complete system flush. The problem I see is trying to get the system flushed properly. The pepto-bismal is now throughout the system..damn.

Any suggestions on the flush? I'm pretty sure it will need to be power flushed. Who has that type of equipment? The dealer? Can I buy a powerflush type machine?

[Jimmiee]

You can flush the system yourself. Buy a good radiator flush. Replace the radiator with a new one. Then remove the thermostat. You will never get all the oil out without removing the thermostat. Flush it once with plain water and drain it. Then add the flush and get it hot. Make sure the heater is on during the flush. Follow the instructions and then fill it with plain water and make sure no oil floats up. You don't really have to do this next step but if it were my truck I would drive it around with just plain water for an hour or so before adding coolant. Make double sure there's no water in the transmission. Once water has contaminated the transmission it's overhaul time. No type of flushing can reverse water damageto your transmission no matter how much oil is used.

[vncj96]

I say kick this guys but, blame it on him, and a tranny should always be checked at operating temp.

[phoebeisis]

Have "WE" decided why/how adding transmission fluid- or over adding it- caused this problem?

Is someone suggesting he overfilled it, and this somehow caused the little transmission cooler-built into the radiator- to fail, and mix trans fluid and coolant??

Don't transmissions have some sort of overflow vent-something that would cause trans fluid to blow out the top?

What is the theory on why this happened?

If there is a vent, then the trans cooler should have been overpressured and failed?

Charlie

[zubbiez]

I think the guy simply put tranny fluid in the overflow resevoir, I know everyone on heres thinking" oh he couldnt have done that".but hey I once seen a guy put fifty gallons of diesel into a hydrolic resevoir on a 250,000$ laser screed, theres no way for tranny fluid to transfer from the transmission lines to you water lines, the guy may not admit to it. but i beat money thats what he did. I wouldnt go with the beat him up Idea, you may want to but he was just being helpful, I think his ego just got in the way of saying he didnt have a clue as to where the tranny fluid goes. you just need to flush your cooling system I dont think youll need to replace your radiator Id just flush it really well, before you start replacing items like that,it may take you several attempts but I think youll be okay.

[Mean_Green_95]

I wouldn't put it past a guy to put trans oil in the overflow reservoir. My buddy almost put a Slick 50 oil treatment in the gas tank because he was going to do a fuel injection service!