Did you check the radiator end caps carefully? The fin junction is a relatively common spot for leaks that are well hidden. The other hiddent spot is the heater core. Some have mixed UV die into the coolant in hopes of locating a leak.

My Cheby had similar symptoms, for years it would loose just a bit of coolant. At about 70,000 miles it got bad enough to start leaving deposits on one of the plugs and then misfiring a bit. Soon thereafter it became obvious of a head gasket issue with plenty of white smoke/steam on startup to notice. For some reason coolant wasn't noticed in the oil nor combustion products in the coolant.

Is there supposed to be any pressure in the recovery bottle?

 

Hi ColdCase,
I am having a difficult time trying to inspect the radiator end caps. I looks like I need to remove the electric fan and shroud assembly to see the end cap connection?? I can't seem to be able to unhook the fan shroud. I also can't figure out how to release/unplug the fan motor connector

 

i had similar in our JkR 3.6. since it was new as well at times could smell it, but never a drop seen. at about 5 years i was doing a PSC upgrade and found that the rubber hose to the overflow tank at the rad was slightly loose. Its just a push on friction thing no clamp. I cut maybe .5" of and the hose fit tight enough thats been over 5 years now. To bad all things dont end as simple.

Long as the Oil is clear no signs of contamination.

 

The cap configuration must vary by year, mine has a traditional radiator cap on the radiator and another plain cap on the recovery bottle.

A small leak needs a bit of pressure to push coolant through.Heat can expand metal enough to open up a crack.

Finding radiator end cap leaks has been talked about before, I'll try to find a reference when I get back. Checking the recovery bottle tubing is a good tip. There have been a few radiator replace threads that may have a usefull tip or two.

 

Dried red toyota coolant in small leaks (hoat I think) looks exactly as your description, white powder that can easily be removed, a bit like salty road water that dried up. Looks like your second picture

 

Maybe another clue? pic is showing the bottom end of the side tank. the bottom edge of the radiator frame almost looks "rinsed off" "cleaner looking" in a very localized area just under the side tank seal. Does OAT coolant dry very quickly?

 

It should not dry very quickly like water, no. Your second picture of the other post would be enough for me to stop searching and either replace the radiator or live with it (and the risks). There is no reason for that white powder to be there IMO the only other reason I would see is dried up road salt, but these isolated spots are very suspicious.

 

Took it into shop and had it pressure tested - combustion by-products are detected in the coolant. No signs of any external leak. Shop says it's a head gasket (between cylinder and water passage, that leaks only when up to full operating temperature). No water in oil. Engine temperature is consistently normal. It has never overheated. The temp gauge never moves much even when towing in mountains. No steam coming out the exhaust. Coolant disappearance has increased from about 4 ounces/year to about 4 ounces in about 5 hours of engine run time.

QUESTION; Will this small amount of coolant in combustion chamber hurt anything if I have to drive it a little bit before my budget allows for the repair?

Also - anybody know a ballpark price for a head gasket replacement on a Pentastar 3.6L in a WK2? Do both head gaskets NEED to be replaced if only one head gasket is leaking? I will have head milled if more that .003" out.
Thank YOU for your experienced advice

 

Coolant leaking into the cylinder may rust the wall, and eventually foul the plug, and then may not start after sitting overnight. If enough leaks in over night you may get an hydrolock condition.

That being said, by daughter drove her cheby a couple years with a small leak. Once she realized it may be a head gasket type problem, she used one of those stop head gasket leak products and it stopped the leak for maybe 3 months. Verified the issue. But be careful with those as the super duty ones, with fiber, will clog heater cores. When it became difficult to start at 70k miles, she saved up and had it repaired with no lasting problems.

How long/miles to you need to drive it?

 

Sounds very much like the wife's 2018 Pacifica. Just went in for an oil change and a P0301 at 83K miles and no overheating, no leaks, but according to the dealer it failed the "chemical block test" and let's start at $5,500 for a tear down and final price that could be closer to $7,500. Hard pass. I can get a pro built long block with 5 year warranty for less than that. It's at my local indy shop looking for a final answer and price.

 

Can anyone tell me where to find a coolant flow diagram? I ask because after putting in a "sealer", new water pump and thermostat, my engine oil temp runs hotter than normal. I'm suspecting that the "sealer" might have partially clogged the oil cooler in the "V" of the block. I want to back flush the oil cooler with the garden hose. According to the "sealer" tech, high flow water should dislodge any possible clog. There is a rubber hose coming off the back of the oil cooler and if I can find the routing of this hose I hope to put the garden hose directly on this oil cooler discharge hose, which I'm hoping "snakes around" to the front of the engine.

 

Oil flows from the engine oil pump to the oil filter housing inlet (1) and to the oil filter element located within the oil filter housing. After the oil is filtered it travels internally through the engine oil cooler and then to the main oil gallery (5).


Coolant flows from the right cylinder block water jacket (3) and from the left cylinder block water jacket (4) into the housing. The coolant flows through the oil cooler and exits the housing from the rear hose nipple (6) where it is returned to the water pump. A coolant by-pass in the housing is designed to direct excessive coolant flow around the oil cooler for continuous circulation.

 

So, "The coolant flows through the oil cooler and exits the housing from the rear hose nipple (6) where it is returned to the water pump"......Would you happen to know if it's the smaller nipple on the water pump that is the hose directly from the oil cooler?

 

The big hose is to the radiator. They small hose is the heater core return. I dunno the oil cooler hose routing.

 

Thanks! I'll try to find a diagram of the antifreeze flow (showing antifreeze hoses/tubes). It would be good if I can find the oil-cooler antifreeze return route hose/tube to be able to back flush oil-cooler antifreeze section