Frothy, Foamy Coolant [Archive] - FSB Forums

: Frothy, Foamy Coolant

Ogeechee 4x4
07-08-2003, 10:47 PM
Ok, so my bronco has always (i've owned it almost 5 years) a coolant leak somewhere. I've always been able to smell coolant after I park it somewhere, yet there's never puddles anywhere....the underside is competely dry (or actually...lined with dried clay) the engine compartment is dusty too...I should be able to tell if something is getting wet. I have to add about a gallon of water every month or so. It's not in the oil or transmission fluid either (i can see/ smell that).

So anyway, I'm getting ready for the Dixie Chapter trip and was going to put a bottle of Bars-Leak in the radiator since I have a 600+ mile trip this weekend. When i took the radiator cap off, it (the cap) was very hot to the touch but instead of fluid spewing out, the coolant was frothy and kinda oozed out of the radiator... kinda like a thick head on a draft beer... Is antifreeze supposed to do this? I didn't think that it was, but I've been wrong before...

07-08-2003, 10:58 PM
yea it can get like that. Sounds like you need to flush the entire system. Thats my recomendation! You will probably find the leak afterwards too. It will clean around it nd leak more so it will be easy to spot. Just get the 5 dollor rad flush thing. You cut your heater hose and put it inbetween the hoses and then run your house garden hose to it and yet it flowwwwwww

07-09-2003, 08:43 AM
As for the leak it could be your freeze plugs. That's where mine is, but it usually burns off due to the heat, and doesn't leak when it's standing still (engine off).

07-09-2003, 03:31 PM
The last time I saw that it was a busted Trans cooler. Trans fluid mixed with coolent.:shrug But yea sometimes old coolent can get that way too. Drain, flush , and refill....:thumbup

07-09-2003, 04:04 PM
When a radiator has foam in it, it's usually caused from air in the cooling system, being drawn in from a small leak. Check the lower hose connections at the radiator and water pump. Also check the necks on the radiator to make sure you don't have a crack where they're soldered on to the tanks.

07-09-2003, 04:56 PM
air in the cooling system

I have seen this once before, cracked head. My wife had a 95 mustang 6 cyclinder with a cracked head. The piston was pushing air into the cooling system, creating a foamy milk shake looking stuff when you took off the radiator cap. Since the piston is only sucking air when the intake valve is open, its not sucking fluid into the cylinder. Only pushing air out on the cumbustion stroke. The first sign of this crack was when the vehicle started to run hot. I dunno if its the same type of scenario in your case, but its just my.02.

If i were in your shoes, i would grab my nearest block tester, using the fluid indicator and run that motor. If you have gas residue in the bubbles in your milk shake, you gotta cracked head, blown gasket, or cracked motor. Using the tester will tell you in 10 minutes whats happenin. good luck.

07-09-2003, 05:08 PM
Here is a pic of the MAC tester,


they want 40 bucks for it, Napa might have one too.

You fill the tube with fluid and shove it on the hole where the radiator cap goes, run the vehicle until its hot and the steam or gas that emits out of your radiator passes through this fluid like a bong. If the liquid changes color, then your combustion chamber has a leak. Also, just for advice. Dont fill your cooling system with hose water. If you use distilled water you wont have the clogging and residue buildup that comes from using tap water with all the minerals and such. The minerals is what gets rusty and clogged and craps up your coolant system after time. So, if you can, use just distilled water.

wheew., ok i am done.

07-09-2003, 10:24 PM
I had, a leak near my throttle body one time. I think there is a hose or tube or something that connects near there. Anyway, this was leaking, I could smell the coolant, what was happening is it was burning off, but like you there was no trace of it under my rig, might want to check there. But definitely start with a radiator flush first.

Ogeechee 4x4
07-09-2003, 10:59 PM
Thanks for all the help guys!I'll give those suggestions and tips a shot. I really hope that it isnt anything major as I don't want to miss the Ocala trip...