samclemmons

Hey. Found info on these. A lot of folks insist not good to use. What are signs they have failed (stuck or whatever). New at vehicle tinkering so some of this may be obvious questions. When bought Jeep April 2014, it started boiling bad. Took to my mechanic and they put new thermostat. Still boiled according to them (pretty much trust these guys). Guy I bought it from was mechanic before new career. My guy wanted to tear into engine. Guy I bought it from wanted to look at it first. He has been real good to me. Helped with few things after I bought. He didn't need to. He put fail-safe thermostat and helped me put new fan clutch on while we were working on it. So far no overheating. Temp gauge stays good. No coolant smell. No low coolant level. Only one thing....sometimes there is a trickling sound after I turn it off. Now I am beginning to think thermostat may be stuck in open position. This is second Alabama summer for it and no problems overheating except trickle sound. It did it last year too I think. Has the fail safe "failed" and what are dangers of this and signs of dangers? Thanks

XJPat

The fail safes don't have the best reputation as you know.
Edit see below, much better wording and advice.

Crash_Course

A fail safe thermostat is exactly that, it is designed in such a way that if it fails for whatever reason, it will do so in the open position to prevent an overheat. An overcooling engine is better than an overheating one in that instance. I've had one of these actually fail, and it worked exactly as designed; in fact the engine in this particular car was running so cool after 45 minutes on the interstate that I had to pull over at a truck stop to allow it to warm up, it was losing so much power. When I was initially under the hood, I found that my hand was resting on top of the radiator as I was looking for the problem... Barely warm to the touch.

If the trickling or gurgling you describe after driving is coming from the coolant reservoir, your radiator cap is allowing coolant to escape into the bottle; this is normal operation. The system is designed to allow coolant to escape the radiator into the reservoir when hot, and as it cools it draws it back into the radiator. If the sound is coming from the radiator itself, you may need a new radiator cap; insufficient system pressure (16 psi is the spec) will not raise the boiling point of the coolant sufficiently to prevent it from boiling. Also, if the ratio of antifreeze to water is less than 50/50, the boiling point will also be lower than what the system is designed for.

It sounds as if you found the problem when the fan clutch was replaced. When these wear out they slip more and pull less air through the radiator.

Hope this is helpful.

samclemmons

Thanks Crash. Since I'm not losing power and radiator is plenty hot after driving, can I assume my failsafe hasn't been triggered and locked in open position?
The sound is definitely a trickle, not gurgle. I'll check cap but I feel the guy who sold it to me would've noticed that after putting in failsafe. He also said we might as well do clutch while doing thermostat. Then helped do most of it. Both replaced at same time. Stand up guy. He worked on a car he sold to someone he didn't know and wouldn't take $$. I supplied parts and beer..lol.
I mix coolant in jug by eye and if it's not 50/50 it should be close. I'll really get under hood next time it happens. Like I said, it's been happening for two summers with no fluctuation in temp or power. Also, plenty of heat in winter.
If I track it down and figure what it is, or have another question bout it, I'll let ya know.

toasterknight

Mag be way out of left field but could it be hot oil draining from the top end?

philthycoder

Can't say whether yours is the same "trickle", but I get a very similar sound when I shut my motor off. After doing some listening and inspecting, turns out it's actually just the oil draining out of the top end after shutoff and trickling back into the pan.

Firestorm500

Cool in the summer, hot in the winter.

Sounds to me like everything is normal.

samclemmons

Yeah. Just all the "failsafes are garbage" stuff I recently read along with mystery trickle, I just wanted reassurance that I'm not setting myself up for engine problems later on.

samclemmons

Didn't think about that. Does it happen every time you shut it off? Mine is sporadic.

DFlintstone

Relax! Just the oil or the mice or something. If it's your cooling system you'll know it.

toasterknight

Aint that the truth.

BlueRidgeMark

Yep. Surprised me the first time I noticed it. I don't know of another engine that does that. It's weird, but normal.



I don't notice it unless I happen to have the hood open, or if I'm standing right in front of it when it's shut off.

jedijeb

4.9L Ford you can hear the oil running down after shutting it off, have heard it in mine for years. Maybe it is something unique to inline engines as I think my 2.5L does it too.

In my F150 I hear the trickling sound when I start it up and it comes from the heater core, I think air is flowing through it when it starts up, but in it the cooling system is at atmospheric pressure.