Engine Leaking water pump. Can I use RTV on the back cover?

evintho

Dirt-Old 20+Year Member
Nov 12, 2003
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Santa Rosa, CA.
Like the title says, it's leaking from the bottom of the rear cover plate. I already pulled the water pump. It's a new Ford Racing M-8501, non reverse rotation cuz I have an early timing cover on the motor. I installed a FelPro gasket on the rear cover and it leaks. Would I be better off just smearing a coat of RTV black onto the back of the pump, then slapping the rear cover on?
 
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I would not and have not hesitated to put Black Gasket Maker like [The Right Stuff] on those gaskets. A thin coat on each side will do. I've also replaced gaskets with the same stuff.

Don't overdue it. Whatever squishes out from beneath the surface goes inside too.

Extra Note: Let it fully cure before running the engine. Full 24 hours if it's inside. Longer if not.
 
UPDATE:
Water pump still leaks! Again, it seems to be coming from the back cover plate just to the side of the weep hole. I used no gaskets. Nothing but RTV Ultra Black 82180 on both the back cover and W/P to timing chain cover. Both the cover and W/P are new. Both surfaces impeccably clean. Smeared a light coating on all surfaces. Tightened the bolts in a crisscross pattern. Once installed, I let it sit for 2 days before I fired it up. The only thing I can think of......does the RTV need to tack up for any length of time before installation?
I've pulled the pump again and cleaned all surfaces thoroughly and waiting for any replies before I reinstall the pump. I don't want to do this again!
 
UPDATE:
Water pump still leaks! Again, it seems to be coming from the back cover plate just to the side of the weep hole. I used no gaskets. Nothing but RTV Ultra Black 82180 on both the back cover and W/P to timing chain cover. Both the cover and W/P are new. Both surfaces impeccably clean. Smeared a light coating on all surfaces. Tightened the bolts in a crisscross pattern. Once installed, I let it sit for 2 days before I fired it up. The only thing I can think of......does the RTV need to tack up for any length of time before installation?
I've pulled the pump again and cleaned all surfaces thoroughly and waiting for any replies before I reinstall the pump. I don't want to do this again!
I’ve never really let it tack up. Usually I’ll just put rtv on, barely tighten and let it sit for a few mins, then torque everything down. I do usually use a gasket and rtv on the water pump, but I’ve put thermostat housings on with just black rtv this way.

I also always pull the back cover plate off and put a thin coat of rtv on the back gasket. Never had one leak.
 
In the shops there's no time to let it tack up smear it on, tighten up, and let it roll. Back in the customers hands as fast as you can get it out.
 
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Runs straight edge across the back of the water pump and see if there is any high/low on the sealing surface. Do the same thing on the timing chain cover.

The plate between the pump and cover should be flat but a little warp is okay.

I use gaskets and RTV every time but not a lot of RTV.
 
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Are you referring to the back plate on the WP? So it's leaking at the bottom between the WP and the back plate?

If so, I had this problem on both my 90 coupe and 93 lx hatch after replacing the WP. I would get a slow drip when car was running. It would stop once the car was off.

I would put permatex form a gasket. And blue loc tite on the back plate bolts.

Honestly it drove me nuts, but after a few heat cycles both stopped leaking.
 
FINAL UPDATE:
Installed the pump with new FelPro gaskets and a thin coating of RTV. Fired it up and it leaks worse than before!!
Walked away and completed some other tasks on the car I had to do. The next day I pulled the pump again (this is getting old)! Cleaned everything up and put a straightedge on the rear cover. There was a gap on each end.......

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So I chucked it in my vise and straightened it. This time I decided to go without gaskets and ran a fairly good bead of RTV on all surfaces. Put it back together and let it sit for 36 hours. Fired it up, brought it up to temperature and no leaks! Not a drop! Finally I think I'm done.
Also, just sitting in the shop idling with the fan on, my SW gauge reads 200*. Is that about normal? I have a 192* thermostat. That's kinda scary for me as my roadster never gets above 180*.
 
That T-stat is not going to start coming off its seat until 192 deg F so full open will be warmer than that. The other thing you need to take into account is that even though it is stamped 192 deg F doesn't necessary mean it will open at that temperature. I have seen the parts store brand units vary +/- 5 degrees on the regular over the years. I run a Robertshaw in both of my cars and have had zero issues and they open at the rated temperature.

Also, the car will run warmer not moving unless you have an electric fan that is worth a crap (Mark VIII, Contour, etc.). You can put a heavy duty clutch on a stock fan and it will help but make sure you have the shroud and you also have the deflectors on either side of the radiator.

 
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I was looking for a Robert Shaw and couldn't find one. Guess I wasn't looking hard enough!
I have an 1100 cfm SPAL fan (the only one that'd fit) and I'm using the Mustang radiator and shroud, no deflectors though. Just wondering if I should drop to a 180* or 185* thermostat?

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200° is where the factory wanted our cars to run. I used to use 2000 jeep cherokee wlectric fans im my mustangs. They'd trim pretty easy and install inside the factory shroud with a few bolts and washers. Now, I run Ford Contour fans. My turbo car likes to be around 203°. I run a 192 thermostat. Cruising temps drop to about 196°. My car never goes above 213°
 
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From what I have gleaned from the experts here, I think it would take about 2500 to 3000 cfm to kool us on an average day even with AC.
you can find the info in the tech/tips forum for the contour fans or search out for one of many builds here that use a couple different wiring setups.
 
go to the JY and get a Contour dual fan, an SN95, or a Taurus fan from a V6. They are OEM, cheap, easily replaceable and pull well over 3000CFM. Couple that with a FAL33165 controller and you are set. Been done 10000 times and multiple write ups here and on the Corral.
 
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I was looking for a Robert Shaw and couldn't find one. Guess I wasn't looking hard enough!
I have an 1100 cfm SPAL fan (the only one that'd fit) and I'm using the Mustang radiator and shroud, no deflectors though. Just wondering if I should drop to a 180* or 185* thermostat?

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:ot: That is a pretty vivid image. What did you take this pic with? I'm guessing that it's [not] a cell phone (even tho the flash is a wash).