Novak Conversions Jeep Wrangler TJ engine mounts

Coolant leak

jrfuda

TJ Enthusiast
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Oct 2, 2024
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115
Location
Fayetteville, NC
Everyone, this is my first post though I've been reading through the forums for about a month now.

I have a new to me 2005 unlimited with 73K miles. When we picked it up from the previous owner there was no indication of a coolant leak. I drove it about 90 miles home on the highway and the wife and I drove it around town a couple of times. About 10 days ago I noticed a tiny puddle of coolant under the Jeep. The coolant appeared to be dripping down from center bottom of the oil pan, but appeared to originate more from the drivers side somewhere above the pan. I checked around with a flashlight and a wifi borescope but could not see anything above the oil pan, nothing near the weep hole (I could not see the actual hole but could all around it) nothing around the gasket or hoses either. I repeated this again today after getting a cooling system pressurization kit and I cannot get it to leak without the engine running. It did leak a little yesterday when I used the Jeep for about 30 minutes breaking in my new BMB vanco big 16 brake kit I had just installed. So no leak pressurized to 18 psi but does leak when actually running.

The leak is small - enough to foul everything up and maybe drop a tablespoon of liquid after it is parked. PO replaced the radiator a year or two ago. Oil looks fine, though I think there is too much oil in it as it is a good bit above the "safe" hole on the dipstick. Engine temp is normal based on my readings here.

I've attached a photo of the oil pan where the coolant is collecting. I know the pan is very rusty, but it seems to be OK for now - the frame and the rest of the jeep just has a bit of surface rust that I'm treating as I work on each section.

Thank you.

Coolant Leak.jpg
 
Might be through the weep hole on your water pump... indicating it's time for a new water pump.

Might be a good time to follow this post:


-Mac
 
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Thank you. I've ordered everything but the radiator since it is rather new and I could not see a leak anywhere on it. I also ordered a thermostat housing since I have to remove it anyway and it is inexpensive.

Thank you again.
 
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Dependent on which hose clamps are on the hoses Ive found leaks are not uncommon from worm type clamps being a tad too loose.
 
Thank you. I ordered all new constant tension clamps to replace the worm clamps.. All of the clamps except the two clamps at the back end of the heater hoses are currently worm clamps... had to order from three different places to get all the clamps! thanks again to the forum members for posting all the sources.
 
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I recently changed my water pump. Only difficult part was getting the fan clutch to break free where it threads on to the pump. I would recommend researching that a little before attempting.
 
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I started replacing my cooling system today.

Shame on me for not checking parts when they arrive. The Mopar water pump I received two weeks ago has a cracked impeller, so now I have to wait three days for the replacement to arrive. I ordered it from Amazon using the link in the cooling system replacement forum. I should have read the reviews that warned about shipping damage.

I've attached photos of the existing pump and the broken replacement. Existing pump is a GMB 120-4340 and has a metal impeller and the Mopar is plastic. Searching around this appears normal, but I was rather surprised by the plastic impeller when I first saw it.

After pulling the thermostat housing, thermostat, and water pump, I'm pretty sure my leak was from the water pump gasket. I also think the last person to change them used some gasket maker in addition to gaskets as there were some off lumps around the gaskets, especially for the stat and housing. I also believe the leak was by one of the bolts. All but one of the bolts came out clean and did not seem to be super torqued. One of the bolts came out very easy and was rusty, so much so that a little pile of rust followed it when I pulled it from the block. Based on where the leak was coming from I'm sure this is where it was leaking. There was no evidence any thread sealant was use on any of these bolts.

Regarding the rusty bolt. Should I be concerned? I need to go back and check the fit. Is there ever a need to redrill and tap the hole?

As far as thread sealant goes, this is new ground for me on the automotive side. I've always used Oatey great white for household plumbing. I assume this is not the correct solution for water pump bolts and the like. What is everyone's preferred thread sealer for water pump and thermostat bolts? I assume I may need something on the temperature sensor and the heater pipe too.

Thank you again

brokenmoparpump.jpg


gmbpump.jpg
 
I'd use Blue Loctite and get yourself a self dispensing tube of Great Stuff RTV. Comes out like spray cheese.

Torque values are all in INCH pounds, not foot pounds.

I'd clean the bolt up on a wire wheel.

A lot of the metal impellers disintegrate over time.

Checking to make sure your thermostat housing and it's mating surface are flat is important...I struggled to get mine to stop leaking. A flat file or sanding block is handy.

-Mac
 
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All but one of the bolts came out clean and did not seem to be super torqued. One of the bolts came out very easy and was rusty, so much so that a little pile of rust followed it when I pulled it from the block. Based on where the leak was coming from I'm sure this is where it was leaking. There was no evidence any thread sealant was use on any of these bolts.

Regarding the rusty bolt. Should I be concerned? I need to go back and check the fit. Is there ever a need to redrill and tap the hole?

As far as thread sealant goes, this is new ground for me on the automotive side. I've always used Oatey great white for household plumbing. I assume this is not the correct solution for water pump bolts and the like. What is everyone's preferred thread sealer for water pump and thermostat bolts? I assume I may need something on the temperature sensor and the heater pipe too.

Thank you again

The torque spec isn't much. 20-some ft/lbs if I recall.

I'd chase the threads to clean them out.

I used teflon on my waterpump bolts.
 
...get yourself a self dispensing tube of Great Stuff RTV. Comes out like spray cheese.

-Mac
That was some awesome advice. The Right Stuff one minute gasket maker saved the day!

But first a fail... I meticulously cleaned the block where the stat housing and water pump would go. Pretty smooth though still a little discoloration. I went from razor scraping to sanding at about 220 and finishing with 400 then a nonwoven abrasive that is like 0000 steel wool (fancy Scotch Brite pad). I chased all the threads and cleaned all surfaces with acetone. I assembled everything, filled up with distilled (this would be flush # 1) and it leaked. Sprayed out the side of the stat when I pressurized everything to 18 psi and dripped somewhere around the water pump. Got better after the gaskets swelled a bit, but still a no go.

I removed everything. The gaskets were well-bound to the block but barely bound to the stat and pump. Is that typical? I cleaned everything again and reassembled using the right stuff gasket maker. I used a couple of drops on the stat to make sure it stayed in place when I installed the housing. I'm only in the shop in the mornings... 430 am to around 6am before I have to get ready for work, so I let it sit overnight.

This morning, I put everything else back on, filled again with distilled and NO LEAKS with the cap off or with it pumped to 18 PSI. Tomorrow I'll drain again and (if clear) replace with the appropriately diluted coolant or flush until clear. I bought undiluted zerex g05. I assume I put in 5.25 quarts of coolant and top off with water to account for whatever water is left in the system?

Thank you all again for your help.
 
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Nice...you did it in two passes. I've had my thermostat housing off twice...first time took 5 passes to seal up, second time twice. My neighbor's WJ got done in one pass.

My 2001 F-250 uses an o-ring. But that's the difference between a 1950s engine and a 90s engine design.

-Mac
 
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All done. Put the coolant in today. I used one of those funnels that seals to where the radiator cap goes. That, combined with the 1/8" weep I drilled in the stat worked out all the air in pretty short order.
 
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Novak Conversions Jeep Wrangler TJ engine mounts