89' FJ62 Overheating Issue, Daily Driver...

[Avery60]

Hey there H8'ers,

Here is a synopsis of what has been going on for the past few months on top of my current no-start problem.

It has heated up HOT on multiple occasions. I always have coolant on hand for this reason, BTW what do y'all use? Anyways, I try to be as vigilant as I can (especially on longer drives) but she has been DRANKIN' it. I have been keen to look for any leaks or puddles/pools/spots and nothing. When it heats up, the fuel gauge also jumps, along with my heart. I slow down, the temperate will drop back down (a few times lower than what it runs typically), I pull over, let her cool off for a while, add coolant steadily, straight into the radiator then the reservoir. It has done it maybe five times the past three months, one time back to back because I was trying to make it to an exit. As my daily driver, with my commute, I should probably be doing preventative maintenance checks every morning, I do my best on top of all things life it just blows my mind how much coolant is being consumed. I feel like an absolute POS not being able to stay on top of maintenance as much as I truly rely on her. Current milage is 275k, 3F-E 4.0 Inline-6. Currently not starting, see my other thread. My thought process is as follows;

I want to to a more thorough visual inspection to search for any leaks, it's just an afterthought when I add coolant, maybe spill a little, and can't differentiate, but like I said, no puddles or spots in the driveway.

Another thought is the thermostat sticking, explaining the sporadic jump in temp and drop and possible over consumption of fluid. An IH8MUD'r suggested an air pocket or with the fuel gauge spike simultaneously, it is a common issue with ground behind cluster. I am asking for more clarification on that one...
Last but not least, I stumbled upon some corrosion to what I think (looking at the manual and it's positioning) is the Water Temperature Switch or Engine Coolant Temperature Sensor Gauge (see pics below).

Possible head gasket but I am not seeing any coolant in the oil or milky color… IDFK

Thought & Prayers???

*while I’m getting some traction, last month on my way into work the RPMS would not go down when accelerating or coming to a stop, even idling at high RPM. Only happened once… I can’t put two in two together right now on top of the no start just thought I’d give it a mention.*

-Avery B.

 

[Devils Paw 80]

I would imagine it's an internal leak, blown HG.

 

[Avery60]

I would imagine it's an internal leak, blown HG.

I didn’t want to say it… But I probably needed to hear it. What are the main indicators and what would be your next step?

Thank you for the comment!

 

[Devils Paw 80]

Main indicators are losing coolant and overheating. You could check for bubbling in radiator with cap off. Other than that, I don't know of a way to confirm it. Might need to have it checked out by a trustworthy shop.

 

[toy_tek]

If the temp is spiking for approximately a minute or so (very rapid rise, the needle is basically pegged full up, then falls back to a "reading") then that's a pretty good indication of the 5v temp/fuel gauge circuit issue you referenced, and not an actual over heat condition. Mine does it pretty regularly, the first few times almost gave me a heart attack. I researched it here, then installed a separate temp gauge for confirmation & redundancy, which has done wonders for my blood pressure too. There are threads here on the subject.

RPM: for starters I would remove the TPS, clean it thoroughly w electrical cleaner and make sure it snaps back to the "zero" position cleanly and consistently. Then re-install and adjust per the FSM. Also check your hand throttle cable is routed correctly (there's a bracket for it near the intake manifold), isn't bound up or otherwise prevented from moving to the full "in" position.

 

[Devils Paw 80]

..Another thought is the thermostat sticking, explaining the sporadic jump in temp and drop and possible over consumption of fluid. An IH8MUD'r suggested an air pocket or with the fuel gauge spike simultaneously, it is a common issue with ground behind cluster. I am asking for more clarification on that one...

Missed that the first time. Yes, you could have a malfunctioning gauge. Stuck thermostat wouldn't explain coolant loss. How much coolant are you losing? I just use the 50/50 green mix easily found at any auto or hardware store.

 

[Avery60]

Missed that the first time. Yes, you could have a malfunctioning gauge. Stuck thermostat wouldn't explain coolant loss. How much coolant are you losing? I just use the 50/50 green mix easily found at any auto or hardware store.

A decent amount, I’m on my fifth gallon in like three months. I drive allot like maybe 380 miles/week. I can’t keep on driving it with this issue ongoing but it’s my only vehicle. I’m already worried I’ve done damage to it overheating multiple times…

 

[cruisermatt]

If it actually took five gallons in three months- do a compression check.

If the fuel gauge is spiking with the temperate gauge that is just the cluster.

Other then that, these trucks have pretty robust cooling systems but if nothing has ever been done to it, we typically replace radiator, water pump, all hoses, heater valve, thermostat, with OEM/CSF and check all sensors and connections. on the 62's that come through. Then they are good to go for another 15 years.

 

[OSS]

All the coolant is going out the exhaust pipe. You may not see evidence just by looking at the oil.
Problem is either a cracked head or leaking head gasket. When the head is finally off, the machine shop can test and inspect for cracks.

 

[cruisermatt]

I went out and did a compression check in addition to diag the no-crank today.
I did notice the fan belt was loose and tightened that up.

Compression #’s
145
145
155
155
140
140

Zero visible external leaks.
It runs fine.

I recommended to just keep an eye on coolant level and keep driving it for now. When it comes to my shop for some real service work I want to put a coolant pressure tester on it.

 

[Elbert]

if you are loosing that much coolant you have a problem and if you don't see evidence of the physical leaks externally , then you need to check your oil for signs of contamination. The coolant is going somewhere and that means (potential cracked block, cracked head, head gasket). I would not trust the OEM temp gauge, install aftermarket quality temp gauge. If the fan clutch has never been replaced ...change it. Back to coolant...you have a problem...I would not be running the engine if you can't find the leak. Not a trival issue.

 

[caladin]

I would imagine it's an internal leak, blown HG.

That is what mine was.

 

[Avery60]

if you are loosing that much coolant you have a problem and if you don't see evidence of the physical leaks externally , then you need to check your oil for signs of contamination. The coolant is going somewhere and that means (potential cracked block, cracked head, head gasket). I would not trust the OEM temp gauge, install aftermarket quality temp gauge. If the fan clutch has never been replaced ...change it. Back to coolant...you have a problem...I would not be running the engine if you can't find the leak. Not a trival issue.

No signs of coolant in the oil... heated up again yesterday and dropped back down. Now the A.T. Oil Temp light is on...

 

[Avery60]

UPDATE: heated up again yesterday... although it did drop down.

A.T. Oil temp light is on near the shifter, checked the trans fluid, seems fine but definitely hot as it was reading over fill line on dipstick...
Coolant level seems fine in radiator when I went to go and fill, although the reservoir is empty... (isn't this just for overflow though?)
I can't afford to keep on having it overheat, if its a head gasket I'm just doing more damage...

Any and all input much appreciated!

 

[Avery60]

That is what mine was.

FML

 

[caladin]

I was lucky, there was a little Exhaust in the coolant, but no coolant in the oil, so I was able to put a bottle of liquid head gasket in, and it's worked perfectly for about 4 years now.

You have to make 100% sure none gets in the oil, because liquid headgasket is
1. A sin,
2. A hack.
3. A liquid that turns into a solid at high temperature.
4. A moral failure of which you should be ashamed (and I am, but I'm also driving my cruiser, and that's the whole point).

#3 is how it seals up the head gasket, but that also means that if any of it gets in your crankcase, it gets into your crankshaft, the bearings, etc and you seize up the motor. So do your due diligence.

Eventually, the motor going to have issues, and I'm about convinced to go SBC instead of fixing it right.

 

[Michael Hanson]

Hi, Pull plugs and compression test ,but probably head gasket.

 

[Avery60]

I was lucky, there was a little Exhaust in the coolant, but no coolant in the oil, so I was able to put a bottle of liquid head gasket in, and it's worked perfectly for about 4 years now.

You have to make 100% sure none gets in the oil, because liquid headgasket is
1. A sin,
2. A hack.
3. A liquid that turns into a solid at high temperature.
4. A moral failure of which you should be ashamed (and I am, but I'm also driving my cruiser, and that's the whole point).

#3 is how it seals up the head gasket, but that also means that if any of it gets in your crankcase, it gets into your crankshaft, the bearings, etc and you seize up the motor. So do your due diligence.

Eventually, the motor going to have issues, and I'm about convinced to go SBC instead of fixing it right.

lol THANKYOU. It’s hard, this is my daily driver. I don’t want to be driving anything else but I also can afford the time and money it would take at this time. I have a vision of where I want the landcruiser to be but realistically I know it’s not going to happen right now. Leak in the gas tank? Slapped on some JB Weld. It is what it is and I’m constantly combatting criticism amongst friends and family to get something “reasonable”. I just can’t part with it, I’ve lived out of this truck before. Drives me crazy that I can’t do what’s always best but I try to give myself some grace. I’ll definitely consider liquid head gasket and will probably be reaching out for more questions about it.

Thanks for your reply

 

[cruisermatt]

Do not put liquid head gasket “sealer” garbage in your engine.

Currently your ONLY indicator that it is actually overheating is the temp gauge. They are just a dummy gauge. If there is nothing in the overflow bottle then the system isn’t pressurizing enough to push past the radiator cap.
I’ve overheated cruisers. The caps pop and hiss and dump coolant into the overflow. It usually has to get to +245 degrees to do that. I have a digital gauge so have actually verified that.

Next time the temp gauge is climbing, have an IR gun (they are cheap at harbor freight). Ready and put it on the radiator hoses, radiator, cylinder head, thermostat housing. Report back here

The next real diagnostic step is a coolant pressure test. With all the spark plugs removed, and compression tester handy at the same time.

 

[cruisermatt]

Hi, Pull plugs and compression test ,but probably head gasket.

Did you read the above post where I went and did a compression check on this truck?