Rednroll

I have a coolant leak on the driver side of my 3.8L engine, running down through the engine mount, and onto the side of the oil pan.

Any idea where this is originating from and what I need to do to repair it?

My 1st guess, is the lower intake manifold gasket may need to be replaced, which doesn't look like a fun job and I'm hoping I'm wrong.

Here's the pics I have.

Rednroll

Well, since no replies I've been doing a lot of Googling and reading. Since I'm leaking coolant, it seems to be a common lower intake manifold gasket leak.

Anyone have this done by a shop and how much did it cost?

This is a good video of someone doing this repair. I may do this myself that way I can spend some time cleaning things up while I have it apart. I'm still not 100% sure this is my problem, but I'm now in the 90% confidence range.

https://www.youtube.com/watch?v=y5bTj2dOW_c I'm at 139K miles. Anything else I should replace while I've got things apart?

I was thinking of replacing the water pump and head gaskets while I'm in there since those have never been replaced. Possibly thermostat as well.

Mark Doiron

Passenger side for me, but it was the intake manifold gasket. I had a professional mechanic friend do it, so any pricing info I gave you probably wouldn't be very informative. I'm not even sure I remember, to tell the truth.

Rednroll

Thanks Mark,
I started shopping around for the parts I would need and was considering getting the Mopar upper gasket replacment kit, which included the following parts and figured I would replace all the gaskets while I was taking the top half of the engine apart.

1= Kit (68003427AB) $200
2= (12)Seal Valve guide (4781072AB)
3= (2)valve cover gaskets (4648987AA)
4= (2)Cylinder head gaskets (4666034AB)
5= (2)exhaust manifold gasket (4892409AA)
6= (1)lower intake gasket (4781034AB)
7= (1)Throttle Body Gasket (4593899AA)
8= (6) Upper intake manifold gaskets (4781580AA)

Then on my lunch break I stopped at the local shop to get an estimate of having them replace the lower intake manifold gasket. They were busy and quoted me $165 which was 1.5 hours of labor @ $85/hr and $40 for the lower intake manifold gasket. Then stated, that was just an off the shoulder estimate and they would need their mechanic to look at my Jeep for a more accurate estimate and said I should come back Wednesday for the real inspection estimate since they were typically booked early in the week. The 1.5 hours seemed very low to me after reading up on what needed to be done and watching a few videos, where I read anywhere between 3 hours to 6 hours is more the norm. This told me the shop likely had never done a JK before since their estimate seemed so low without having the mechanic look at it.

After I left the shop, I went to eat and while I was driving my temp light came on and I had just topped off the fluid yesterday after I noticed the leak which told me my leak was pretty bad since I only drove about 25 miles to work today.

I stopped in a nearby Meijers and picked up some distilled water and topped off the coolant, so I could make it home. It took 1.5 gallons of water. I stopped at the dealership and picked up the lower intake manifold gasket and the 6 upper manifold gaskets. Damn upper gaskets are like rubber bands and were $10 each!!! I thought when I gave them the P/N for the upper gasket, it included all 6 for that price, but I guess not. Anyways, since my leak seems pretty bad, I'm jumping head first into this now.

The ghost gave itself up today when the temp light came on. Here's a nice puddle of coolant sitting right next to that lower intake manifold seam.


So wish me luck, I'm jumping in head 1st!!! Stay tuned in case I run into any problems and have questions.

karls10jk

Subscribed.....165k miles here and I'm sure this is inevitable. My radiator just started leaking out of the side so hopefully that'll be my solution for now. Intake gaskets don't look fun.

Rednroll

Hindsight 20/20, that's where my coolant system problems seemed to start.

1st it was the infamous poor heater performance which I "thought" was a HC problem. Then shortly after that, my radiator sprung a leak which I was hoping would fix my heater problem, but it didn't. Now my lower intake manifold sprung a leak, where again I'm hoping once I fix that, then it also fixes my heater problem.

My thought is my coolant system had tiny leaks in the intake manifold gasket and the radiator causing my heater problems due to air entering the system. I fix the radiator, that then causes more pressure in the system which then causes a bigger leak in the lower intake manifold gasket. So I'm hoping once I get this fix, my heater comes back to working good.

I actually made a circulating pump system with a hot water heater to circulate hot CLR through the heater core, hoping I could clear out any clogs but haven't gotten around to running it to try it out....now I'm hoping I don't have to and my HC is fine.

139K miles on my ticker currently, so still right behind you in mileage.

Mark Doiron

When my manifold gasket started leaking it was just a few months before the Al-Can trip. I asked Tim (the mechanic friend) if he thought there was anything else to do to the Jeep before the trip. He said that the radiators usually go around 200K miles, and I was setting at something like 188K. He suggested that while normally he'd say just run it until it fails, in my case that could be in the middle of nowhere above the Arctic Circle. "If I was driving up there, I'd put a new radiator in." So we did that. And to answer the question I just begged, after reading around for various aftermarket radiators, I went with the OEM. Too many complaints of having to repeat the work because of a leaky new radiator.

Rednroll

Well, you're definitely right. This is a lot of work to replace a freaking gasket. I didn't get as far as I hoped last night. I got the upper manifold removed. When I'm done, I'll have a step-by-step to post up for you if you ever need it, with all the tools I used to do the job. Since this is my 1st time doing this kind of thing, as I go along I write down each step and the tools I used on each step, then put the nuts/bolts in zip lock bags with the step number on it, so that way when it's time to put it all back together I'll just do the steps in reverse and know what tool to grab for re-assembly and therefore hopefully not have any of those extra parts left over when I'm done.

I'm now on step #21, upper intake manifold removed. Time to start working on getting the lower off.


Crawling under the Jeep, it looks like that lower intake manifold gasket must have started leaking from both sides yesterday because it wasn't that way the day before when I 1st noticed it. It's been 90F and very humid the past 2 days in my area, which is odd for this time of year, so maybe that had something to do with it. It's looking pretty nasty under there with that coolant dripping all over both cats on each side and everything else. Over the past 2 days it seemed to go from, "Hey, I think I have a coolant leak on the driver's side of my engine....to holy sh*t it's leaking from everywhere."

Rednroll

Well, aint this a kick in the Fing pants!!!

I was on the last step of removing the bolts from the lower intake manifold and was just about to pull it off. There's 8 bolts that holds the lower manifold to the rest of the engine. I pull 7 of those bolts out and notice the 8th one already seemed to be out. So having all my step by step notes in hand, I start thinking "maybe I already pulled that one out and I just need to go back in my instructions and figure out where I pulled it out at, because I'll need all 8 bolts to properly torque the lower manifold back down. Nope...I didn't find that 8th bolt anywhere. So I put one of the other mounting bolts inside the mounting hole and it only goes half way down. One of the bolts had broken off over time!!! No wonder I'm leaking coolant from out of my engine all over the place!!!

Notice the left side mounting hole, it looks like there was a bolt there that was freshly removed which it was and the right side mounting hole looks like the bolt has been missing for awhile. Yeah, that right side hole the bolt was broken off and that is likely the source of my lower intake manifold leaking coolant. Now I need to go figure out what the part number is for those 13mm lower intake studs. The dealership is now closed, which means I won't be able to finish this up until tomorrow, "if" I can get a replacement bolt. I'm hoping I can still get this manifold pulled off and get the broken bolt out of there.

Rednroll

Ahhhhh!!! It gets even worse. There is a metal bracket on the firewall behind the manifold with a metal tab on it that holds the back of the lower intake manifold down. You can't lift the manifold straight up to remove it because of this tab. So to remove the manifold, you need to 1st slide if forward to clear that metal tab but since I've got a broken bolt in one of the manifold mounting holes, I can't slide the manifold forward.

F YOU CHRYSLER ENGINEERS!!! AND F YOUR STUPID RED ELECTRICAL LOCKING TABS AS WELL!!!