Coolant Leak Transmission (1 Viewer)

[ckennedy]

My 1993 FZJ80 has recently developed a steady coolant leak (a rapid drip to be specific) from what I assume is on top of the trans somewhere. It comes down the driver side of trans and drips of the lip of the pan.

When I installed the donor 1fzfe I bypassed the rear heater hoses so I thought that would rule out the easy solution. I performed a compression test to rule out a HG failure but all cylinders read ~190psi.

Should I take it to a shop for a leak down test? Time to drop the trans for a peak? Any help is appreciated. TIA.

 

[A2ShedsJackson]

My 1993 FZJ80 has recently developed a steady coolant leak (a rapid drip to be specific) from what I assume is on top of the trans somewhere. It comes down the driver side of trans and drips of the lip of the pan.

When I installed the donor 1fzfe I bypassed the rear heater hoses so I thought that would rule out the easy solution. I performed a compression test to rule out a HG failure but all cylinders read ~190psi.

Should I take it to a shop for a leak down test? Time to drop the trans for a peak? Any help is appreciated. TIA.

Check the PHH (pesky heater hose) and the hoses that run to the firewall at the heater control valve.

PHH - Pesky Heater Hose. A 100 mm length of 16mm (5/8 inch) straight heater hose located at the extreme LH rear corner of the 1FZ engine cylinder head. So named because it is not the easiest thing to change-out even under ideal conditions.

PHH

When doing the PHH replacement, is silicon high temp hose recommended, and what size hose is needed?

forum.ih8mud.com

Coolant leak by rear heater hoses/firewall - 97 LX450 - 1FZ-FE

Hello, I am experiencing a coolant leak and it looks like there is a hose that has exploded and is no longer connected. Please see pics below. Is this hose that got disintegrated part of the rear heat system? Can someone please help me identify or confirm what parts are needed to fix this or...

forum.ih8mud.com

 

[ckennedy]

Check the PHH (pesky heater hose) and the hoses that run to the firewall at the heater control valve.

PHH - Pesky Heater Hose. A 100 mm length of 16mm (5/8 inch) straight heater hose located at the extreme LH rear corner of the 1FZ engine cylinder head. So named because it is not the easiest thing to change-out even under ideal conditions.

PHH

When doing the PHH replacement, is silicon high temp hose recommended, and what size hose is needed?

forum.ih8mud.com

Coolant leak by rear heater hoses/firewall - 97 LX450 - 1FZ-FE

Hello, I am experiencing a coolant leak and it looks like there is a hose that has exploded and is no longer connected. Please see pics below. Is this hose that got disintegrated part of the rear heat system? Can someone please help me identify or confirm what parts are needed to fix this or...

forum.ih8mud.com

Thanks, I should have mentioned i checked the PHH and replaced it during the swap. I will check heater core lines.

 

[A2ShedsJackson]

Let us know what it is. Solved mysteries are always fun. Not that it's related, but I did an oil change on my '94 FZJ80 while you were checking your hoses and noticed that my radiator cap is bad. Saved me from a lot of wasted time tomorrow.

 

[ckennedy]

So I checked my PHH and its bone dry. I also fondled the heater control valve and the remaining heater hoses and all are dry.

Anywhere else above the trans I should look?

 

[Maccuscharlie]

Could you post a photo of the drip?

 

[flintknapper]

Right next to the PHH (just in front of it) is another hose/port that routes coolant to your throttle body. A leak there could blow back onto the trans.

 

[ckennedy]

Thanks for all the replies guys. I took the rig to a shop. Turns out I blew my HG. I thought a compression test was a sure fire way to diagnose a HG failure. My gasket failed leaking coolant but maintained cylinder pressure. I have the LC stripped and am getting the head inspected early next week.

 

[Kernal]

Post up some photos of the headgasket in place if it's not too late to show
the rest of us where/how it failed.

 

[flintknapper]

Thanks for all the replies guys. I took the rig to a shop. Turns out I blew my HG. I thought a compression test was a sure fire way to diagnose a HG failure. My gasket failed leaking coolant but maintained cylinder pressure. I have the LC stripped and am getting the head inspected early next week.

^^^^

Common misnomer. Head Gaskets can fail in a number of ways.

Your's was blown to outside coolant leak.

 

[ckennedy]

Here's a photo of the HG in place

 

[flintknapper]

Another #6 cylinder failure looks like. Mine failed on that cylinder too.

 

[graham5david]

Mine failed there too. I couldn't figure out what was leaking. I finally put a mirror behind the head and found it. Mine would run down the transmission and pool in the transmission wire loom and was dripping of the rear of the transmission.

 

[A2ShedsJackson]

Thanks for all the replies guys. I took the rig to a shop. Turns out I blew my HG. I thought a compression test was a sure fire way to diagnose a HG failure. My gasket failed leaking coolant but maintained cylinder pressure. I have the LC stripped and am getting the head inspected early next week.

Sorry to hear that it's the head gasket. If it makes you feel any better while you were first checking for leaks a week ago I discovered that my radiator cap was bad. A few days after replacing the cap I discovered a pin hole in the radiator.

I have a new 4 row all aluminum radiator on the way. $200 shipped from NJ. 4 Row Radiator For Landcruiser HDJ80/HZJ80 1HZ/1HD 4.2L Diesel Manual 1990-1998 | eBay - https://www.ebay.com/itm/203293078860 I already have a separate trans cooler since this may or may not come with an internal cooler on the bottom of the tank. I'll let everyone know how the swap goes since it looks like it will take a few mods to work, even though they say that it's a drop in replacement. I hope that it will not require me to drag out the Tig. I have a CNC machine shop in house as well. Aluminum is pretty easy to work with.

 

[A2ShedsJackson]

Sorry to hear that it's the head gasket. If it makes you feel any better while you were first checking for leaks a week ago I discovered that my radiator cap was bad. A few days after replacing the cap I discovered a pin hole in the radiator.

I have a new 4 row all aluminum radiator on the way. $200 shipped from NJ. 4 Row Radiator For Landcruiser HDJ80/HZJ80 1HZ/1HD 4.2L Diesel Manual 1990-1998 | eBay - https://www.ebay.com/itm/203293078860 I already have a separate trans cooler since this may or may not come with an internal cooler on the bottom of the tank. I'll let everyone know how the swap goes since it looks like it will take a few mods to work, even though they say that it's a drop in replacement. I hope that it will not require me to drag out the Tig. I have a CNC machine shop in house as well. Aluminum is pretty easy to work with.

Replaced the radiator, big hoses and clamps several weeks ago. Noticed that my coolant level was 1 liter (~1 quart) or so low every few days but never saw a drip. I'd smell antifreeze while driving on hot days but never see a leak. Got worried it was the head gasket again or heater core. Replaced the radiator cap and tightened up the constant tension clamps on the PHH and all the new clamps for the big hoses.

The other day after a quick trip I noticed a substantial drip from the rear of the engine but could not spot the leak and it stopped after 1-2 minutes. Got back home and topped it off after cool down. Took it out tonight for a test drive and sure enough after 10 minutes of highway driving I came to a stop to check for leaks and there it was again. Drove back and put it right up on the lift. Took off the driver side front wheel. A HAH! Pinhole in the hose that runs from the head up to the throttle body. Sneaky, very very sneaky.

 

[flintknapper]

Replaced the radiator, big hoses and clamps several weeks ago. Noticed that my coolant level was 1 liter (~1 quart) or so low every few days but never saw a drip. I'd smell antifreeze while driving on hot days but never see a leak. Got worried it was the head gasket again or heater core. Replaced the radiator cap and tightened up the constant tension clamps on the PHH and all the new clamps for the big hoses.

The other day after a quick trip I noticed a substantial drip from the rear of the engine but could not spot the leak and it stopped after 1-2 minutes. Got back home and topped it off after cool down. Took it out tonight for a test drive and sure enough after 10 minutes of highway driving I came to a stop to check for leaks and there it was again. Drove back and put it right up on the lift. Took off the driver side front wheel. A HAH! Pinhole in the hose that runs from the head up to the throttle body. Sneaky, very very sneaky.

Yep.

That is a hard one to detect sometimes. That hose originates from the head, just in front of the PHH. The hose then snakes its way under the intake up to the throttle body to provide cooling. When the vehicle is underway, small leaks simply blow back on the engine. Glad you found it. Pinhole leaks are tough to find when they AREN'T hidden.

 

[cvenom96]

Had this happen to mine on the way back from TN a few weeks ago. I had just done the HG, replace PHH and throttle body hose, all of that stuff. It was fine there and while wheeling. Got on the road heading back and first gas stop it was dripping from somewhere in that area. Running down the transmission, firewall, onto starter but it was too hot to reach up in and feel plus I couldn't see. Then it just stopped. Hmmm ok cranked it up and no leak. Drove some more and would notice the temp move every now and then. Stop and it would drip a bit then quit again. Just kept adding coolant till I got home. Next morning I noticed the clamp on the TB coolant hose was about where the end of the tube was and the hose itself had pushed back. Basically the spring clamp wasn't holding it tight enough. It was the old one so much have just been worn out. Replaced it and it's been good since.