The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support Fuel Injector Clinic
Please Support ExtremePSI

No matter what I do, my oil pan is always leaking!

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

KianaLynn

Proven Member
34
4
Nov 2, 2016
Helena, Montana
Alright so here’s a back story. Before the motor rebuild, I never had a problem with my oil pan leaking. After the motor rebuild, it would leak constantly. I’ve tried using a gasket with sealant, and just sealant. But it still continues to leak. Before the motor rebuild I’ve used a gasket with the sealant and never had a problem. So after trying it both ways, I decided to order a new oil pan. Just to eliminate the oil pan being a problem. I always made sure that my oil pans were flat before putting it back on. But now, I can’t seem to stop it from leaking no matter what I do. And it’s onlt leaking on the timing belt side. So I investigated that area a little more and discovered that my valve cover was leaking right behind the cam gears so I took care of that. I also noticed that the oil pressure unit was leaking so I got that replaced as well. It’s getting pretty close to the next oil change and I wanted to see if anyone has suggestions on what else I could do and if there’s any preferences on what should be used.
 
When you replaced the oil pan, did you torque the bolts down in the correct pattern?
Yep. I even kept looking in the manual just to make sure I was doing it correctly. And had my other half sit there with me to make sure I was tightening everything down in the correct pattern and didn’t miss any bolts.
 
I think that’s what I ended up doing this last time was letting it sit for most of the day before putting oil in it. I was thinking about just putting sealant on, letting it sit the majority of the day and overnight, and then putting oil in to make sure that it is dry. I just don’t know what I’m doing wrong this time. It’s becoming extremely irritating.
 
Make sure the silicone bead runs inside the bolt holes. Also, it may help to not tighten/torque down the oil pan bolts before it sets so that it doesn't just get squished out. Maybe tighten it halfway, and then torque it down after it sets. I know it's not recommended, but I used a gasket (because the flatness of the oil pan flange was questionable) and sealant without problems.
 
If you haven't mounted it already, try the following:

Clean both block and pan surfaces of any residual gasket/silicone/oil etc. Inspect both surfaces for any visible cracks or high spots (such as chipped metal sticking up around bolt holes or towards the edges, believe me small things like that can ruin gasket surfaces and not seal).

Place the pan on the block dry. Easier if your block is on a stand, install all the proper pan bolts but just snug, not tight. Take a hammer and hammer the flange all the way around. Snug, hammer in a clockwise or anticlockwise rotation, snug again, hammer again. Keep doing this until you can visibly see both surfaces being more or less flat against each other.

Take everything off, clean it once more, apply a ~4mm black silicone or Mitsubond as shown in the following picture. Make sure you go around but 'behind' each bolt hole, and continue the line within the grooves. Don't wait too long after applying the sealant (max 5 minutes), install it onto the block as accurately as possible to reduce smudging, insert all the bolts (beware of 2 shorties under timing belt) and snug finger tight. Then tighten in 2-3 stages as per FSM or in a circular pattern. If torqued properly, and if you used a 4mm sealant bead, a nice, thin line should squish out evenly around the oil pan, roughly 2-3mm thick or so.

Leave the drain plug OFF and let it air dry for at least 10-15 hours before putting oil in and heat cycling it.

You must be logged in to view this image or video.
 
I personally use Permatex Grey, very similar to Mitsubond, It is vibration/oil resistant and thick.
The RightStuff is very good but is a mf'r to get cleaned off if you need to and it holds so good that you, or I, at least, have bent a oil pan flange just trying to get the pan off. Hell I think it would have been fine with no bolts. That was on a Saturn motor but it was alot like our 4g's. Just my experiences.
 
I had a constant leak on my 1g, just annoying weepage, cleaned the pan all up spotless, let the engine idle while on jackstands, rolled underneath and watched for leaks.
Turns out my pan had a hair line crack not visible by eye but oil returning to the pan would weep out where the pan was stamped/formed on the radius.
It was probably from when I jammed a screwdriver in there to pop it off at one point, I now just use a skinny puddy knife type scraper to cut through the rtv rather than pry it off by force, tapping it between the block and pan all the way around.
 
I'm not down talking any advice, but you dont want to bead the rtv out of the can.

Ive always used the smear approach and evenly and lightly coat the pan

You make a fat bead like that and its just going to squish back into the oil pan

A flat even coating makes sure youre not just going to goo up the inside of your pan. And makes it easier to just finger tighten all of the bolts instead of just unevenly squishing the rtv bead as you go around the pan.

let the ultra grey rtv cure for 24hours (yes that is the specified cure time before exposing to oil)
 
I'm not down talking any advice, but you dont want to bead the rtv out of the can.

Ive always used the smear approach and evenly and lightly coat the pan

You make a fat bead like that and its just going to squish back into the oil pan

A flat even coating makes sure youre not just going to goo up the inside of your pan. And makes it easier to just finger tighten all of the bolts instead of just unevenly squishing the rtv bead as you go around the pan.

let the ultra grey rtv cure for 24hours (yes that is the specified cure time before exposing to oil)

The grooves for where the bead is meant to be placed, along with the recommended bead thickness (4mm) is engineered precisely so that as you tighten the pan down properly and let it sit, it squishes out enough sealant to form an even layer over the full pan surface, while completely filling the grooves to further reinforce the seal. If you put the 4mm bead as shown in the manual, torque it down, then take it off, you'll find that it's a nice, even coating , with very little sticking inside or outside the pan.

A good quality silicone/sealant will not flake off and clog your oil pickup, for example. Additionally, the smear method might sound good on paper, and you might have just as good results, but ultimately it's not the "correct", or "recommended" way of applying it. You don't have precise control over how thick your layer will end up after smearing it, either by hand or using a flat tool like a credit card. This is the exact same scenario as when applying thermal paste to a CPU chip. You don't smear the compound in advance and then install the heatsink. You simply apply a pea-sized blob of paste in the center, and as you tighten the heatsink, it evenly spreads it out in a 360 degree span. This is essentially what happens when mating the pan to the block and tightening it up. If you smear the sealant on the pan flange, then tighten it down, you risk pushing out just enough sealant that it wont properly seal, and hot oil will find its way through.

I just wanted to give some more technical reasoning for why the FSM lists this specific procedure. This is not to say that other methods will not work, but it is simply the most effective way. If the pan otherwise has structural damage, or oil somehow gets over the sealant while installing, then it will always leak.
 
Just to confirm, this is a 4g63 platform and not a 420a you're working on correct? I ask because I have a 99 GS in addition to my GSX, and the 420a blocks have a bed plate design. Upon rebuilding my 420a several years ago (broken timing belt) upon first assembly and startup in the car I had a pretty bad leak between the block and bed plate. This may not pertain to you at all, but throwing it out there just in case...
 
i had this problem on my car and i tried 2 x to seal the pan . finally i put dye in the engine oil and found that the leak was coming from the timing belt side of the engine . taking everything apart i found the leak coming from behind the engine mount bracket . after removing the bolts there was one bolt that went into an oil galley . what i did was to put sealer on the threads and now there is no more oil leaking . this leak started after i did my motor . i didn't realize that there was an oil galley there until i did further investigation.
 
Dye is your friend when they are elusive. And it doesn't take much and a UV light so I like that idea.
 
Dye is great! That's how I discovered a cracked transmission case once... Also, it does really help to start with a clean trans/engine before doing such a test.
 
Just to confirm, this is a 4g63 platform and not a 420a you're working on correct? I ask because I have a 99 GS in addition to my GSX, and the 420a blocks have a bed plate design. Upon rebuilding my 420a several years ago (broken timing belt) upon first assembly and startup in the car I had a pretty bad leak between the block and bed plate. This may not pertain to you at all, but throwing it out there just in case...
back in the day, I bought a built 420a shortblock. i had the same problem with it (upon first assembly and startup in the car I had a pretty bad leak between the block and bed plate). It ended up being because the idiot that assembled it forgot to put in the o-ring that goes between the bedplate and block.
You must be logged in to view this image or video.


------------------------------------------------------------------------

Clean oil free surfaces are key, sealer/gasket maker won't adhere and seal if there is oil film on the surfaces.
Great point.
Its best to make sure the bolts and bolt holes are oil free also.


I have used just about every kind of permatex and loctite rtv there is. None of them works as good as
Hondabond HT.
 
HONDA WHAT???? :barf: :p
 
Also make sure the oil pump gasket isn't leaking down onto the pan making it look like the pan. It sounds like you need to pressure wash the hell out of it, stick some dye in it and run it before changing the oil.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top