surfh2o

99 4runner V6. 140k It appears I have oil in my radiator! Just did an oil change and it's perfect. The A/T fluid looks good. I've heard that there's more pressure in the crank case than the radiator and it's probably a one way leak. I flushed the coolant, ran cleaner in it for a week, flushed and it looks the same. I just don't know what to do at this point. Should I get a true diag on it or buy a product that claims to seal the leak? Am I looking at a head gasket? If so should I just do it or wait til it blows? Thanks for any feedback, I'm desperate.

83

Don't use any of the "products". If there's a leak it needs to be fixed. If it's happening that fast, it seems like you'd notice performance issues if it was the headgasket, but that's my first thought. I would definitely take it in to find out how you're getting oil in there. Oh and if it's a headgasket get it fixed. You don't want that to really go out and cause your entire engine to need rebuilding. I know it's different with cars like Subarus, where people will run the car with a slight headgasket leak for tens of thousands of miles, and just make sure their coolant is full, but I don't think you want to do that with a Toyota.

surfh2o

Thanks for your thoughts. I recently bought it and I had a 98 Tacoma V6 manual tranny and it was faster than the 4runner, but it should be. Using my truck as a comparison, the 4runner seems to run pretty good. I've dogged it a bit just see how she runs and no problems. 90mph no problem. I guess I should get a true diag....

83

Yeah, I don't know V6's really, but I know when the headgasked went on my old truck I could hardly keep it running. On other people's, with slight leaks and not full blown..blown headgaskets, it seems like it will run really rough when first started, but once it's warm the metal will expand enough to cut off the leak and it then runs fine.

Oil isn't a great coolant, but getting oil in the coolant is better than coolant in the oil, so as long as you aren't getting coolant in the oil, you're not in as bad of shape. Coolant in oil is not good for your bearings etc. I know there are other places for the two to mix, other than headgasket failure, but I don't know enough to know how to check all that out.

surfh2o

Yeah like I said it appears to be running good. I would almost say it runs excellent. I've also heard that there are other places for it to mix. I'm gonna have to take it in for a true diag. I was just thinking maybe someone would say oh get some magic formula and it will solve all your problems. Thanks for your help though. I'll try to remember to post after I get someone to check it out.

myyota

If the tranny oil cooler in the radiator is leaking that could be the problem.

surfh2o

Do you know if there is a way to check that?
Thanks

TechWrench

Check the color of the oil in the radiator. If it has a redish tint, it is probably from the auto trans. If it is brown or blackish, it is engine oil. Quite often when you get oil in the cooling system, it will foam, and the foam color will help determine where it is coming from. If it is coming from the trans, there is only one way for trans fluid to cross into the cooling system side, through the trans cooler loop inside the radiator. You have two choices, have the radiator repaired/replaced, of remove the trans fluid lines to the radiator, plug the input and output ports in the radiator and install an aftermarket aux cooler. The second option is not the best choice, but I have seen it done. Also, if it is trans fluid in the radiator, then you have a good chance there is some water in the trans, and you should have it flushed and refilled once the radiator problem is fixed.

If you have engine oil in the cooling system, most likely you have a head gasket problem.

surfh2o

The color is grey milky and sits on the top. It's got to be engine oil. It overheated quick yesterday and no heat in the cab. That's most likely a t-stat right? I just need to drive it to the repair shop. It wasn't overheating before and I just flushed the system. So its either something I did or the t-stat is blocked. I've heard that the cooling system should hold about 2 gallons, I couldn't fit that much and was more like 1.5gals..

Adam F

you have an air pocket. park the truck on an incline. remove the rad cap and run it. keep it topped off, this should burp the system.

surfh2o

I topped the coolant off and started it up, added a little more coolant. Blasted the heat and it came to temp and held this time. Maybe it burped itself somehow. I still might do an incline, but it seems fine now. I took it to the Toyota shop and told him about the oil in the radiator. He said first of all it is very rare for the 3.4's to gave head gasket failure. He said if there was a head leak then there should be water in the oil. He said a gasket leak is not just a one way leak and would show in the oil. When I pointed out the after market radiator. He said well they replaced it for a reason and was probably associated with the tranny. His thinks it is just residue left over from that and it's hard to get out cause it doesn't mix well. He said it could be a leak occurring at the water pump. All he said was watch the oil. It was cool they didn't try to rob me but I wish they could've done some kind of diagnostic. This could make sense cause when I changed the oil the level was good and the oil was nice and dirty.

DavidAlexander

Any word on what this was?

wjwerdna

they can't hook a computer to your truck and tell you where it is leaking... all they will do is same thing you can do in this situation, check your oil, check your tranny, check your radiator, etc.

oh, and post a pic if you can... is there a lot??? when you flushed coolant, did you empty/flush/clean your overflow for radiator? if there is crap in that, it will get sucked back into radiator

DavidAlexander

I like how the tech says "if there is not water in the oil, it is not the head". What did he do, look at the dipstick or take a guess. I read the OP said he just changed the oil.

I am sure the tech would "not worry" about it if it was his truck.

surfh2o

I did clean out the overflow and now it's all sludgy again. I did just change the oil. The last oil looked just like dirty oil, it looked good. I was thinking if it was a leak and the oil is clean now then in theory the gray oily color I'm seeing would be lighter in color now. Not the case. It looks the same. The tranny fluid looks good. I heard if it's a tranny leak then the oily color would be more pinkish. I'm starting the believe the tech in that the radiator was replaced for some reason and it's possible residue. He said it could be a water pump leak. When I flushed the Rad. the first time it looked good at first til it got to the oil sitting on the top. After I ran the cleaner for a week I flushed it hot to get a better mix. Now it's back on top again. I'm really not sure what to do at this point. What else can I do? Pressure tests?? Send the oil/coolant/tranny fluid off for testing(would that even tell me anything)

surfh2o

Oh and to answer specific questions. I will try to post a pic this weekend. Most of it ends up in the overflow since it sits on the top. Maybe I'll just keep cleaning it out. He did look at the stick. It looked like perfectly clean oil. He didn't say don't worry about. Just said keep an eye on it.

DavidAlexander

Ill share this story whith you. When I was 17 and had worked for a few years saving money, my dad co-signed on a nice Mercedes 190e 2.6 that just came off lease. My parents knew the owner of the dealer and I got a great deal. So for a little over ten grand I got my first car. But I knew nothing about how to take care of them.

I had this grey globby stuff that would show up on top of the overflow tank. I took it to the mercedes dealer in town and they gave me the "just keep an eye on it". Well it ran fine with the globs until it burst a radiator hose (a few months later). I took it back to the dealer and they replaced the hose and didn't have any more concern about the globs, just to keep an eye on it. A few months later, the car started having trouble cooling. I took it to a German Auto shop in town this time.

They immediately told me that it was oil in the coolant and it was lowering the cooling properties of the coolant. They also quickly diagnosed my previous hose failure as oil impregnation, which caused it to loose strength and burst. The Dealership missed this for over a year.

The head gasket was leaking and all the time that I was driving around with the small amount of oil in the coolant it was gradually overheating my engine. By the time I got to the Euro shop the head was warped and needed to be resurfaced. Total was over $1000 dollars and that was over ten years ago.

The car never ran bad and never got into the red except the final time when I had it towed to the shop. So for me this would not be a little problem. I listened to a tech at the dealer once and he missed an easy diagnosis, even after he replaced the burst radiator hose. That cost me alot of time and money fixing the problem further down the line.

Sorry for the novel. Just wanted to share because it seems so similiar to your problem. D

And the dealer I purchased it from is in another city a few hours a way, not the dealer that missed the problem.

mt_goat

Other than the headgasket (most likely) one other possiblity is the oil cooler. I never heard of one having a mixing problem but its something to think about. The oil cooler is about 6" or 8" to the rear of the oil filter and has 2 coolant hoses that run to it (a long one from the t-stat housing area and a short one from the block).

What color coolant are you using?

wjwerdna

yeah, just because it is not common (HG) doesn't mean it hasn't begun leaking. There are variations in manufacturing of vehicles