FJ40 w/rebuilt 2F engine after sitting for several years, now have overheating issues (1 Viewer)

[FJnewlife]

Hello,
Sorry for the long post but I'm hoping it provides enough detail...
I have a 1977 FJ40 that sat in my garage for 20+ years with the engine pulled while waiting for me to find time & $$$ for a dream V8 conversion with an Advance Adapters kit, Ranger transfer case, power steering ...etc. I finally settled last summer on just having the original 2F engine rebuilt by a machine shop a couple hours away. Then later, I discovered a closer Land Cruiser shop & let them do the re-install. The very day I got it back, I didn't notice the temp gauge climbing and it got seriously hot to the point the local shop had to replace a couple valves and resurface the head but even after that, it continues to have overheating problems and the local shop is out of ideas. In cooler weather (50ish & lower) it runs fine with the temp needle settling between the first & half marks but when the weather warms up & within just a few miles the gauge climbs steadily & will go over the 3/4 mark if I don't pull over & let it cool or coast downhill in neutral. On one trip, the gauge was nearing the 3/4 mark and I was looking for a place to pull off when I noticed it settle back down suddenly so I thought AHA, the thermostat was stuck & finally opened up. So when I got home, I replaced it with a new 190 degree stat but the problem continues. There are no visible leaks and the coolant stays filled to the brim. During the engine install and later during my process of elimination, pretty much all the cooling components have been replaced - thermostat, hoses, water pump, fan clutch, radiator cap. The radiator itself is an unknown to me since it was replaced by the installer with a boxy aluminum one after he found an un-repairable hole in my original. He also found cracks in the exhaust manifold and replaced it with a header but since it runs so close to the engine, I'm wondering if that might be contributing to the overheating. So I'm hoping some of you might have ideas before I try a new radiator (closer to original style), sending unit & gauge to round out the possible component replacements. Also, does anyone know what actual temperatures the marks on my original FJ gauge correspond to?

Thanks in advance for any help you can offer!

 

[3_puppies]

have you got actual temps? with a temp gun
do you have a fan shroud?
is the fan mounted the correct way?
there are enough guys out there running headers without issue that I don't think that would be an issue
OEM waterpump?

 

[Steamer]

Hello and welcome to the forum. Some good pics under the hood from various positions and angles would really help. Good pics sometimes reveal obvious problems, short cut around some questions and often encourage others to chime in to help you solve your issue. Plus, we all just like looking at cruiser pics

 

[GA Architect]

The very day I got it back, I didn't notice the temp gauge climbing and it got seriously hot to the point the local shop had to replace a couple valves and resurface the head but even after that, it continues to have overheating problems and the local shop is out of ideas.

Any possibility that the head gasket isn't installed correctly or isn't the correct head gasket?

 

[Billinator]

I may have an idea. My 72 sat for 10 years in a dirt lot, waiting for me to grab it. When I got it home, my brother (who worked at Toyota Forklift) got it running in 5 minutes. I also had a heating problem. Found out that the water jackets were all gunked up with rust and crud. There is a water drain bolt on the back drivers side of the block. Pull it out, drain everything. Then flush the heater lines(especially the one that comes out of the top of the block) and the thermostat housing. I literally took the water hose on high to each of these areas and finally got all the junk out of the block. It took a good 45 minutes. If this is not the issue, its a good practice anyway, and the only cost is the water!

 

[rainingagain]

When it's warmed up, pop the radiator cap and see if the fluid its "flowing". This will verify that your thermostat is opening and there no major blockages. And that your water pump it actually working.

 

[FJnewlife]

I didn't see flow the couple of previous times I checked and my only potential verification of flow was the one time I saw the gauge drop from 3/4 back to around the first mark while driving. The water pump and thermostat are new with less than 50 miles on each but I'll keep checking this. Thanks

 

[FJnewlife]

I may have an idea. My 72 sat for 10 years in a dirt lot, waiting for me to grab it. When I got it home, my brother (who worked at Toyota Forklift) got it running in 5 minutes. I also had a heating problem. Found out that the water jackets were all gunked up with rust and crud. There is a water drain bolt on the back drivers side of the block. Pull it out, drain everything. Then flush the heater lines(especially the one that comes out of the top of the block) and the thermostat housing. I literally took the water hose on high to each of these areas and finally got all the junk out of the block. It took a good 45 minutes. If this is not the issue, its a good practice anyway, and the only cost is the water!

I'm working my way thru responses and this might be related to my issue. The engine shop was supposed to have rotted out the block & head before rebuilding and hopefully this would have cleaned the jackets too but maybe something was missed and that might explain why I'm not able to quickly confirm water flow thru the cap. I'll respond back on this when I have follow-up info. Thanks

 

[FJnewlife]

Any possibility that the head gasket isn't installed correctly or isn't the correct head gasket?

Regarding the head gasket, the local shop that did the engine install did say the rebuilder had installed the head gasket backwards. They found this when they had to redo the headwork after the initial serious overheating but they confirmed it's all correct now. They do a lot of FJ40 work and I would have had them do my rebuild too had I known they were there before I took the engine to the other guy. Live & learn. Thanks

 

[SteveH]

I vote for your radiator being clogged with junk from the block. I had this happen when I installed an engine that had been sitting for 17 years. It would only overhead on the freeway, which is often an indication of poor radiator performance. A new radiator fixed it.

 

[rainingagain]

I didn't see flow the couple of previous times I checked and my only potential verification of flow was the one time I saw the gauge drop from 3/4 back to around the first mark while driving. The water pump and thermostat are new with less than 50 miles on each but I'll keep checking this. Thanks

Thermostat could also be installed backwards.

 

[FJnewlife]

Hello and welcome to the forum. Some good pics under the hood from various positions and angles would really help. Good pics sometimes reveal obvious problems, short cut around some questions and often encourage others to chime in to help you solve your issue. Plus, we all just like looking at cruiser pics

Regarding pictures, my FJ is no raving beauty, except maybe to me, but the stories it could tell. Attached are some pics and I'm working to respond to some of the other posts too.

 

[FJnewlife]

Thermostat could also be installed backwards.

Here's a pic of how the thermostat ended up going in...

 

[rainingagain]

Here's a pic of how the thermostat ended up going in...

View attachment 2553977

That looks correct to me.

If you want to 100% rule out the thermostat, you can heat it up in some water on the stove and validate that it's actually opening.

Thanks for the pics, she's a beaut! Nice job avoiding the bezel police.

 

[FJnewlife]

have you got actual temps? with a temp gun
do you have a fan shroud?
is the fan mounted the correct way?
there are enough guys out there running headers without issue that I don't think that would be an issue
OEM waterpump?

I do not have a temp gun but will by the end of today - it would be very useful in this situation. You can see the fan shroud in the pics and it looks OK to me except that the fan is only have under the should. Not sure if that's normal or an issue. Good to hear on the headers so I'll discount that as contributing to my problem. Thanks

 

[bhsdriller]

As other have mentioned i'd try flushing the block again

 

[John McVicker]

On your t stat, do you have the rubber ‘O’ ring that goes to the TOP of the t stat?

 

[pigmony]

I'm guessing a blockage somewhere; most likely in the block or in the radiator. It sounds like the shop that did the original rebuild may not have been so great on getting the details right, so they may not have done a great job of getting the water jacket cleaned out. I think I'd give the whole system a good flush and see where that got me.

 

[Billinator]

Remember to pull the drain on drivers side of block

 

[Michael Hanson]

Hi, I’d flush till clean, and install a Gano filter in the upper radiator hose. Allows you to see the flow of antifreeze and trap crud from the system. I’d also get a new air cleaner hose and run it too the front of the cruiser. Did Bobby redo the engine? Mike