Valley pan gasket or a hidden hose

[E39ChrisM]

Yesterday, took the e39 out for a spin. Was doing some spirited driving, after I heard my serpentine belt squeaking which was odd to me. Pulled over, popped the hood and their was coolant all over the engine, not a lot but a good amount . Looked under the car and there was a coolant leak; bummer.

It was awesome that I was a mile away from my home, took the car immediately back and shut it off. It was night time, so I waited until this morning to look at the vehicle. Turned it on, on a cold start and no visible leak...until two minutes passed by and there she blows, the leak starts happening. Looked around on the upper passenger side of the engine and I couldn't find nothing there that was leaking, I don't have a jack at home atm so I can't look under the car while it's running.

I will be taking the car to the local indy shop to put it on the ramp soon. I did a cooling system overhaul recently and everything that was changed has been holding up fine. I only changed the hoses that connect to the water pump, thermostat, and radiator. Previous owner did the valley pan job in the summer of 2013. I bought the car in summer of 2016

What do you guys think before I take it to the shop, will it be a hose or a sneaky leak from the valley pan? https://youtu.be/wLGLVB1pATA

[M5XTu]

It could be one of the O-rings for the bypass tubes coming from the water pump to back side of engine. You will need to buy a total of 4 O-rings.


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[E39ChrisM]

Put the car on the ramp while running and the coolant seemed like it was leaking from the middle of the transmission and engine. Couldn't really locate where.

We put the car back down from the ramp and with the help of a flashlight & patience, we located the leak and it's indeed the valley pan gasket. There was a coolant river under the intake manifold and the main leak was pretty close to where the thermostat is located. It had strong tides. Valley pan gasket will be done soon IMAG2305.jpg

[motion]

As always do as you feel is best. If you're going in for the valley pan and coolant pipe "O" ring consider replacing the accumlator cross over gaskets. I prefer purchasing new OEM fasteners and replacing the accumulator bolts with studs and washer faced nuts. If the shop has a tig machine, you can also consider welding the coolant pipes to the accumlator which makes changing the water pump in the future easier and you won't disturb the rear "O" rings. Also there are other seals, profile gaskets, "O" rings, etc, on the intake manifold and fuel delivery parts, that may be due to be changed.

[killian665]

Do not weld your pipes to the crossover.

[JimLev]

Do not weld your pipes to the crossover.

Ditto, that's just asking for a heap more trouble and unwanted aggravation.

[geargrinder]

LOL. That is hilarious. +1 to KilliansRed. Strongly advise against that.

For one, those O-rings are surprisingly un-problematic, unless you are really ham-fisted and unwise in janking the tubes around, so it's basically solving a problem that doesn't exist.

For two, if you ever had to pull the valley pan again, or change knock sensors, you'd have actually to unbolt the rear crossover manifold to get them out of the way, instead of removing the water pump and then just popping the tubes out.

[E39ChrisM]

Finally, the job is done. Changed out a lot of gaskets and put 4 new Mahle o-rings on the crossover pipes. The gasket I received with the valley pan was so thin, we couldn't slap it on like that so we added some gasket maker to seal it good and I could sleep at night knowing nothing will leak after installation.

On start up after installation, the car was misfiring for about 10 seconds, thought something was up. But after about 20 seconds the car started idling really well and was breathing again.

I had to do the bleeding process again when it comes to the cooling system and I would say I am an expert now in getting it done well, because of my past experiences lol.

Anyways if you any of you bump into my thread and are doing the exact same job, below are the part numbers for the o-rings and a great gasketmaker I recommend. You will need two of each o-ring (small & large) The crossover pipe gaskets (part number) that are attached to back of the engine is "C32304". You will need two of them. I recommend Victor Reinz or Mahle brand . NO local part store is going to have these gaskets so always be prepared for a few days of delay in receiving the items OR you can always buy them online with two day shipping which is more convenient.

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