1996 FZJ80 - Cooling system issues after work done? (1 Viewer)

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Oct 27, 2012
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Wenatchee, WA
Hi all, over the last year or so, I have been doing a bunch of preventative maintenance on my 80 (cooling system refresh/replace, exhaust, few other thing).

Ever since replacing the radiator, thermostat, water pump, and all cooling hoses, it's been weird about the thermostat opening when it should/heat coming on. At first, the thermostat was definitely broken. Replaced that and other parts and it still did it. Replaced the thermostat twice, determined it wasn't that. Had it back to the shop for weeks to diagnose. Finally came back that it was a hose that had gotten sludge in it -- toward the back, hard to see, etc.

Anyway, finally got it back after doing the rear main and a few other things and I'm getting ready to sell it on Bring a Trailer. Today, as I'm out snapping pictures and letting it run to charge the battery (not my daily driver at this point), I notice the heater/thermostat/etc. is STILL doing the same thing by not opening. Here's the weird part...

I revved the engine up to about 2-3k RPM (from idle) and heat began coming through. Needless to say, I was pissed. But what I noticed was that after I let my foot off the accelerator pedal and the engine went back down to idle, the heat STOPPED. Press on the pedal, heat comes back.

Obviously now I'm pretty confused, but what's worse is I'm trying to sell it and I won't sell it if it's got an issue like this because I don't know what it is. Is it coolant system hardware or leaks? Could it be the head gasket??? Any other ideas?

Any help would be *greatly* appreciated!
 
I find that I get more heat as the water pump turns faster. More volume through the system perhaps.
 
you have air in your system, your heater valve is broken or the HVAC slider is broken.
 
Recheck that thermostat to be certain is installed correctly. If they are just following the way they found it, it could be wrong. The orientation of the t-stat and the placement of the O-ring can cause issues.

It may also be a good time to get a test kit to check about the possibility of a HG failure.
 
Sorry all, busy week at work. Just getting to replies now. Thank you for so many replies!


you have air in your system, your heater valve is broken or the HVAC slider is broken.

Yeah, I got the feeling about the air (had it happen before). What's the protocol for venting/burping the cooling system on this?

Also, thanks for the "heater valve" comment and HVAC slider. I'll look up the heater valve (unfamiliar with it). You did mean the HVAC slider on the interior controls, right?

Recheck that thermostat to be certain is installed correctly. If they are just following the way they found it, it could be wrong. The orientation of the t-stat and the placement of the O-ring can cause issues.

It may also be a good time to get a test kit to check about the possibility of a HG failure.

I'm not familiar with how the thermostat should be correctly installed. I'll search, but if you have a quick link it would be much appreciated.

Also, I've never had cause to worry about HG failure in any of my other vehicles. Where can I pick up a test kit for this? Thank you in advance!
 
There is a lisle funnel you use to burp air out. Park or jack the front up. Put the funnel on and allow the truck to run and give it gas while adding coolant. I’m over simplifying this so please do a deeper dive
 
I'm not familiar with how the thermostat should be correctly installed. I'll search, but if you have a quick link it would be much appreciated.

Also, I've never had cause to worry about HG failure in any of my other vehicles. Where can I pick up a test kit for this? Thank you in advance!
Here's the lowdown, including an illustration:
1FZFE Thermostat gasket replacement - https://forum.ih8mud.com/threads/1fzfe-thermostat-gasket-replacement.1222522/

Most good auto parts stores have a test kit available for checking your coolant to see if there are signs of a HG failure.
 
Replace your heater valve with OEM and make sure the control cable is adjusted correctly.
 
Thank you guys for all the replies, I've got a day off work tomorrow, and I'm going to try and see what I can figure out, assuming it doesn't piss rain all day.
 
Okay, so I didn't have time to deal with anything, and was on a short timeline, so I sent it into the Toyota dealership yesterday with this list of issues and fixes we had all talked about

Apparently it's got a bad head gasket. 🤦😢

Anybody have opinions on roughly how much something like this should cost with an 80 series?

I've gotten quotes between $4,500, 5800, and 3,000, the more expensive ones being replacing a lot of other stuff like the water pump and things that I've already done, and the $3,000 one just basically being the gasket etc.

Is that pretty typical? I definitely would never sell it like this, but since I am selling it I certainly don't want to put any more money in it since I've already put in six grand over the last year.
 
On the positive side, I would hope that all the new work done on the truck, especially sporting a sleek new top of the line OEM head gasket... Lol...would help push the value in its auction on BaT, so there is that silver lining.
 
That's a bummer for sure.
If the rig is in good shape (no rust, OEM parts, etc...) given the current demand for these trucks you could, with patience, get good money for it.
People with the will (and money) to rebuild up from a solid platform will look at it with interest
Good luck!
Cheers!
 
Thats a bummer. How many miles on it?
189k. To be fair, I just replaced the rear main as well, so I feel like maybe that was part of it. Oddly, it ran fine before I started doing all this preventive maintenance on it. 🤦
 
Hey look I don’t trust dealerships

I had one tell me my factory lockers where installed aftermarket and they can’t fix it.
it was just a seized actuator. Fixed it myself and regret the $300 diagnose fee

id get a compression test done and a blackstone analysis report to see if there is coolant in the oil. I have a feeling they are taking your wallet for a ride. My .02
 
Yeah, unfortunately, dealers are really not interested or qualified to work on these trucks. They are trained to maintain the current generation of Toyotas. Find a local Cruiser shop and get a second opinion.
 
For those of you who suggested getting a cruiser specific shop, they are running multiple months out even to get it in to diagnose.

Furthermore, the shop that did all the refresh work on the coolant system was recommended by the cruiser shop up here. Without going too deep into detail, let's just say I will never take it there again.

Before taking it in to the dealership here, I had a conversation about whether they had worked on any FJ80s before. Apparently, they've had quite a few just within the last year, some doing legitimate refresh / overhaul work.

It may not be the ideal situation, but it's the situation I've got right now unfortunately.

And for the record, the dealership quoted me about 3,200 for the head gasket which I felt was fair considering all the other places I had called. Also, the cruiser specific shop here that does really good work told me that 3,000 on the low end also.
 

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