Water pump doesn't seal

AlaskanDsm · Jan 5, 2012

I did a search to see if anyone else this issue but I did not see it so I am just posting here to get some thoughts on the problem that I am having.

Recently, My OEM water pump with only 36K miles on it starting leaking heavily from the weep hole. So I went out and purchased a Rock auto replacement. I didnt have the money for OEM anyways. I went to install the new said water pump and took the new seal and very lightly coated in black silicone. once I got the water pump into place and pressed onto the water pipe, I went to bolt down the water pump but here is where I get confused.

The original water pump sat flush against the block no problem. This new pump I could not get to sit flat on the block surface to have piece of mind before bolting it down. I thought that maybe the o-ring from the water pump side was just being tight, so I verified the gasket was positioned properly and bolted the water pump down. I gave it a good visual inspection and everything looked fine. I let it dry overnight.

The next morning I came out and decided to check with water to see if it was leaking. After fillin it almost full, I started seeing coolant on the ground from the water pump leaking from the seal at the bottom.

What would cause something like this to happen? I exchanged the water pump already for another one just in case. The only thing I can come up with currently is that the water pipe is keeping the water pump from being able to seal against the block. Has anyone ever heard of that causing issues even though it has not moved from the OEM pump?

Also is there any other possibilites that could cause that proble, outside of a defective water pump, water pipe, or misalignment of the gasket??

Rsawd95dsm · Jan 5, 2012

gotta be a defect id return the thing and inspect the next one they give you with the one your returning

MrKelly · Jan 5, 2012

I had issues the first few times I tried this also. Your best bet, which has always worked for me is as follows. 1 don't use silicone as the fiber/paper style gaskets we use for our water pumps doesn't work well with silicon or rtv, instead stop by your local parts store and get a fresh gasket and spray. they will have a spray in a can for paper gaskets, most engine builders use this on every gasket on that side of the block also make sure the area of the block that the gasket makes contact with is clean. It's made by mr.gasket, pro seal, or the one I like made by 3m. It's usually right by the rtv. 2 you should disconnect the front water pipe from the thermostat housing and block, you'll need 2 new orings to reinstall it, don't take it out of the car just give enough room to put the water pump on and then slide the pipe into the water pump once the pump is torqued down right, don't put any type of sealer on the orings either. Just wet them with clean coolant and make sure the grove they sit in is clean of build up or debris. Follow those steps and you should be golden.

AlaskanDsm · Jan 5, 2012

I have already returned the first one and I have a second one waiting to go on.

I have a feeling that it would not have mattered how the gasket was being sealed either with silicone, paper, or a mix. I believe that it was just not sealing tightly against the block. During my attempt to replace the pump the first time I made sure the clean the mating surface thoroughly. Everything else except unbolting the water pipe I have done only because it is a real pain in the ass to get to the bolt that holds the water pipe in place on the passenger side of the engine...

The only thing I can think of is that the water pipe sticking out too far to the pump to seal.

And yes I do realize I could just go out there and try to put it on but I won't be able to do so until this weekend. I am just trying to prepare a bit better for any additional problems I might run into.

luv2rallye · Jan 5, 2012

Make sure you install the crossover pipe o-ring properly: http://www.dsmtuners.com/forums/newbie-forum/309982-coolant-leak.html#post151625392.

AlaskanDsm · Jan 5, 2012

luv2rallye, Thanks for the info but I already knew this. The leak was not coming from the water pipe but from the bottom of the pump where it connects to the block. The o-ring used is already on the water pipe and was drenched before I put the pump on.

NOSLO2PT0 · Jan 6, 2012

Did you scrape all of the old gasket off the engine before installing the new water pump? That old gasket gets pretty crusty and hard and is a major PITA to get off with the engine in the car.

AlaskanDsm · Jan 7, 2012

Well I finally got a chance to get out there and see if I could get the second new water pump on. It honestly went on without a hitch so I am thinking that the first one must have some kind of a problem when I was installing it. Thanks for the help.

DSMDEMON93 · Jan 10, 2012

Be careful with any autopart store components, they are literally "a dime a dozen". I went through so many thermostats at Kragen, because every new one was broken. Remember: You get what you pay for.

AlaskanDsm · Jan 11, 2012

I totally agree and normally, I would have just gone and gotten OEM but I couldnt afford to shell out over $100 at the time and so if this one only lasts me 5,000 miles, it was worth the $35 I spent on it.

bryanwheat · Jan 11, 2012

MrKelly said:
I had issues the first few times I tried this also. Your best bet, which has always worked for me is as follows. 1 don't use silicone as the fiber/paper style gaskets we use for our water pumps doesn't work well with silicon or rtv, instead stop by your local parts store and get a fresh gasket and spray. they will have a spray in a can for paper gaskets, most engine builders use this on every gasket on that side of the block also make sure the area of the block that the gasket makes contact with is clean. It's made by mr.gasket, pro seal, or the one I like made by 3m. It's usually right by the rtv. 2 you should disconnect the front water pipe from the thermostat housing and block, you'll need 2 new orings to reinstall it, don't take it out of the car just give enough room to put the water pump on and then slide the pipe into the water pump once the pump is torqued down right, don't put any type of sealer on the orings either. Just wet them with clean coolant and make sure the grove they sit in is clean of build up or debris. Follow those steps and you should be golden.

I have used grey rtv on probably 200 pumps with paper gaskets of many different makes and models over the years and have yet to have a problem. It's all in how you prep the surface, and how you use the product.

MrKelly · Jan 15, 2012

Apples and oranges. I guess that's why Mitsubishi used rtv on the pumps and they call for it in the manuals. Actually they don't and engine builders I know don't use it on that side of the block either Examples Dogbox racing, turbotrix, magnus, graveyard motorsports. Paper gaskets can breakdown when rtv is applied to them and it can cause uneven torque on the gasket when tightening because as you said it's how you use it, and if you read the back of the rtv your supposed to let it set up. So what do you do put it on the block wait for it to set up then put the gasket on and then another layer and wait?or are you smearing it on the paper and tightening it down defeating the purpose of the rtv all together. Just get the spray, clean the surface correctly and torque it correctly. Works for Mitsubishi, most 8 sec dsm's and for me personally every time.

Jon Lane · Jan 28, 2015

I just went through three gaskets in a month. The old gasket in the rebuild motor went bad and started leaking. A new paper gasket installed dry on a new pump leaked immediately. A second paper gasket coated liberally with copper spray leaked even worse. In both cases neither gasket saw coolant for 24 hours.

I don't understand why RTV alone isn't sufficient. It's OEM procedure on all sorts of high end cars. They apply a 1/4" bead and immediately bolt the parts together using moderate torque. A thin skin remains and fills all the joints.

Doesn't it seem that any time there's paper contacting water under pressure eventually the paper is going to fail? I don't discount thousands of examples of paper-only installations, but given my luck and the common use of RTV by original makers, I'm really tempted to try it.

pauleyman · Jan 30, 2015

The most common failure I see us not getting all of the old gasket off. You need to feel around and make sure. To each his own on sealants but I use gasket spray on paper gaskets and nothing more. Never had a failure on any paper gasket I've ever installed on any type of component.

Jon Lane · Feb 14, 2015

Just completed a third water pump reassembly last week. Coolant-type RTV on both sides of the paper gasket and light pressure to bolt things together. This time it's dry as a bone. Apparently RTV seals the paper and things become watertight.

Why water pump gaskets are paper in the first place is a mystery, but apparently they all are.

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