'85 FJ60 Engine Coolant not heating w engine running

[Geosfj60]

I have gremlins in my '85 Toyota Land Cruiser fj60. Had radiator leaking so pulled it and had a shop run through it to make it like new. Changed out the thermostat (and the gasket that doesn't want to sit on top) and have noticed it is not heating up. Checked (took it apart and put it back together) 4 different times to ensure that the gasket was placed correctly. Put the thermostat on the stove in water to make sure it opens at 180 degrees (about 182ish). Working fine. After running for 10 min. no heat. Felt the hose leading into the radiator and from the radiator, not hot. Hose coming off the thermostat housing (bypass), warm but not hot. It's cold here, but the engine block is also not heating up too much. Even ran it up and down a hill a few times, no big change. Kinda at a loss. Water Pump? Any suggestions/insights would be appreciated. Engine/radiator/cooling system is not leaking coolant.

 

[micruz60]

Might need to burp the cooling system?
Also be sure the rear heater in cab is on full blast with front heater.

 

[Geosfj60]

Good catch. Should have put that in the description of the problem. Ran it with the heater on (front and rear), little heat. Ran it with Radiator cap off to burp system, didn't really heat up.

 

[Output Shaft]

10 to 11 minutes after starting up a cold engine, fast idling, (1200 rpm) the coolant should be up to 190° F when ambient temp is 55°F.

Ensure that the thermostat isn't upside down. And that it is a Toyota thermostat. Don't use the 180° thermostat designed for the FJ40.

Photo below of IR temp gun 11 minutes after starting 55°F engine.

 

[Geosfj60]

10 to 11 minutes after starting up a cold engine, fast idling, (1200 rpm) the coolant should be up to 190° F when ambient temp is 55°F.

Ensure that the thermostat isn't upside down. And that it is a Toyota thermostat. Don't use the 180° thermostat designed for the FJ40.

Photo below of IR temp gun 11 minutes after starting 55°F engine.

View attachment 1360529

Thanks, after 10 min. upper and lower hoses are just barely warm to the touch. Good note on the 190 degree thermostat. The parts stores here only have the 180 F, I'll have to dive in the garbage can and see what the old one was or track down a 190 F after I figure out whats going on.

 

[micruz60]

Interesting.

An fj40 has a 2F engine, with or without oil cooler.

An fj60 has a 2F engine, with oil cooler.

Why would there be a different t-stat, because 2F?

 

[Output Shaft]

There's a few theories as to why Toyota changed the temp rating of the t-stats in later 2Fs from 180 to 190°.

1981 and later Cruisers with 2F gas engine got the 190ºF thermostat (88ºC)
PN: 90916-03052

The temp increase in the thermostat was also increased on the diesels as well (which don't have smog tests). So the reason for the higher temp thermostat was not just an emissions thing. It may have been that newer oils could take the heat, and possibly through testing it may have been found that the engines run more efficiently at that temp and last longer too.

But the old 2Fs in the older FJ40s still are specified to use the 180° t-stat... So who knows?

 

[3_puppies]

what ratio coolant to H2O are you running? Too much coolant doesn't work well.

Decades ago dad bought a car and had very little heat, mechanic checked it and it was straight coolant. changed out to 50-50 mix and all was good.

 

[teamdonzi]

I second the motion to make sure you are using a Toyota thermostat, not one from local auto parts. I had similar issue and the non Toyota part was just a bit skinny, allowing the coolant to flow past all the time. My temp would barely creep up off the bottom of the gauge. Replaced with Toyota part and fresh gaskets, and problem solved, temp is mid way on the gauge. Runs much better and heat is HOT.

 

[gregnash]

what ratio coolant to H2O are you running? Too much coolant doesn't work well.

Decades ago dad bought a car and had very little heat, mechanic checked it and it was straight coolant. changed out to 50-50 mix and all was good.

So are you talking about creating your own 50/50 mix or the pre-diluted stuff? I thought many had stated with these trucks it is better to do a 1/3 - 2/3 (distilled water/coolant mix) than the true 50/50? This could be why my heater never truly gets hot after the head was rebuilt this last year.

 

[Elbert]

about the only thing that makes sense is an air pocket in the cooling system. If the thermostat is installed correctly with the rubber washer.
its likely going to take longer than 10min sitting at idle to do anything. Fill up the system with coolant, turn both heaters to full hot, have the front of the truck higher than the rear and let the engine run for some time until thermostat cycles. Hopefully you have an aftermarket gauge to note the actual temp in F. Once the thermostat cycles (which should be easy to note) top off cooling system with coolant. Depending on how cold where you are....it might take some time for thermostat to cycle.

Yes there are other ways to "burp" the system and there are some nice funnels...etc, but if you don't have that...the above works. The thermostat has to cycle or you are not going to be able to "burp" the system of air.

 

[gregnash]

about the only thing that makes sense is an air pocket in the cooling system. If the thermostat is installed correctly with the rubber washer.
its likely going to take longer than 10min sitting at idle to do anything. Fill up the system with coolant, turn both heaters to full hot, have the front of the truck higher than the rear and let the engine run for some time until thermostat cycles. Hopefully you have an aftermarket gauge to note the actual temp in F. Once the thermostat cycles (which should be easy to note) top off cooling system with coolant. Depending on how cold where you are....it might take some time for thermostat to cycle.

Yes there are other ways to "burp" the system and there are some nice funnels...etc, but if you don't have that...the above works. The thermostat has to cycle or you are not going to be able to "burp" the system of air.

I have burped the system multiple times (actually haven't in a number of months, not since before I broke my leg) but still can't seem to get that heat back. If it weren't so damn cold out I would flush the heater core and then burp the system. Wondering also if I just have too much "coolant" (full strength green) in the system and not enough water.

 

[Elbert]

I have burped the system multiple times (actually haven't in a number of months, not since before I broke my leg) but still can't seem to get that heat back. If it weren't so damn cold out I would flush the heater core and then burp the system. Wondering also if I just have too much "coolant" (full strength green) in the system and not enough water.

My above msg was in regard to op posting...but his issue seemed to be engine not warming up according to what was stated. If engine comes up to temp then obviously heaters should work. If no heat then its a game of confirming thermostat/rubber washer, heater control valve operation, and potentially clogged heater cores..

I run 50/50 mix of coolant/water. The coolant mix should not have anything to do with the issue noted above.

 

[gregnash]

hmmmm... well I guess I should check the coolant level again and prop the front end up to see if there is a bubble moving around. That would explain the intermittent cooler temps coming out of the truck.

 

[3_puppies]

So are you talking about creating your own 50/50 mix or the pre-diluted stuff? I thought many had stated with these trucks it is better to do a 1/3 - 2/3 (distilled water/coolant mix) than the true 50/50? This could be why my heater never truly gets hot after the head was rebuilt this last year.

50/50 mix of coolant and distilled water is all you need, 50/50 should be good to -40 F or C,

My above msg was in regard to op posting...but his issue seemed to be engine not warming up according to what was stated. If engine comes up to temp then obviously heaters should work. If no heat then its a game of confirming thermostat/rubber washer, heater control valve operation, and potentially clogged heater cores..

I run 50/50 mix of coolant/water. The coolant mix should not have anything to do with the issue noted above.

original poster @Geosfj60 states engine getting warm not hot so issue is engine heating not heater related

coolant mix is related to engine heating, too much coolant will adversely affect the heating of the engine.

 

[gregnash]

Yeah looks like I am going to have to grab a bit of time and check the level and add some distilled water.. Think I am about out so will have to run to the store.

 

[Elbert]

how does the mix of coolant to water have a tangible substantive impact to engine reaching operating temp? I can follow how it might have a very minor impact but not tracking otherwise. I dont' think we are talking about someone running 100% coolant.

 

[Output Shaft]

This link explains the heat capacity of coolant vs water and a lot of other really neat cooling issues related to cars.

Bottom line though, every 2F creates tons of heat really fast regardless of radiator, water pump or coolant. A cool running engine or one that takes forever to warm up is the result of a malfunctioning thermostat.

Things you should know about coolant | hellafunctional

 

[roscoFJ73]

Water Pump? Any suggestions/insights would be appreciated. Engine/radiator/cooling system is not leaking coolant.

I was wondering if you had checked the actual flow from the top hose? I don't think it would be a water pump. They virtually have to destroy themselves to stop pumping.
I was thinking maybe you have a blockage somewhere.

 

[Sacto60]

This link explains the heat capacity of coolant vs water and a lot of other really neat cooling issues related to cars.

Bottom line though, every 2F creates tons of heat really fast regardless of radiator, water pump or coolant. A cool running engine or one that takes forever to warm up is the result of a malfunctioning thermostat.

Things you should know about coolant | hellafunctional

Dang, my 60 has been running just above the bottom of the gauge too. I drove hard up into the Sierras with heater going, then wheeled in the snow for a few hours, but still, the gauge was just off the bottom. I'll try that burp method, roll up on the sidewalk and see if I can get any changes.