Haynes is telling me to use Merpol on my new gasket for my water pump. The water pump directions tell me to use a tacky sealant.

I cant even find Merpol online or at auto parts store.

Since it came with a gasket, I see no need in RTV gasket maker.

What should I do? Im thinking just install with paper gasket that came with water pump with no RTV. I cleaned off old gasket material off block - clean as a whistle. What's Merpol?

Thanks in advance.

 

Lets start with the Haynes manual is stupid with everything. Lol.

Second, use red RTV. Not whatever this merpol is. You need the RTV as the adhesive. If you don't put it on there, it is likely to leak when you start it. The red RTV is high temp. I use it for water/coolant applications.

Third...if its not a metal gasket you need to use an RTV. Rubber gaskets are not in need of RTV either. But all paper and cork gaskets use an RTV. Red is the best for high temp areas. Black is best for oil resistance.

 

I will disagree. I have put together engines from bare blocks, and don't use anything except where there are unusual shapes or surfaces. Flat to flat will make a good seal using a gasket made from a shoe box. Or a Cheerios box. Or a factory gasket.
You don't need any sealant other than on the bolt threads as the holes are bored through to the water jacket.
If you want to keep the paper gasket from falling out of place, use some thread to tie it to the stat cover, thread the bolts, cut the thread, and pull it out.
I find it difficult to keep proper torque when using a smear of sealant, as the sealant will slowly ooze out of place, and lower the torque below spec.
Do what you want, but I won't be using it, and didn't. I did use RTV on the housing bolt threads, and haven't had a problem.
I have never heard of "Merpol", so any comment pro or con would be speculation of the highest order.
tom

 

I agree with tomw.

 

Thank you so much for your replies. I bought a gray RTV sealant that has specifically advertised on the tube that it is for water pumps. It is Permatex brand.

I think I have decided to put a small bead of this "gasket maker" on the body of the water pump and press the paper gasket onto the water pump body to hold the gasket on the water pump. I will also then put a small bead of RTV around the outline of the old gasket, including the bolt holes. I will then insert the water pump and torque.

Haynes says to torque water pump bolts to 89 inch pounds for a DOHC 4 cylinder engine, but my torque wrench starts at I think 120 inch pounds. So I am a little lost here.

Thank you all so much. This stuff makes me wish I had gone to be a mechanic rather than a science teacher .

 

mickey1 said: "I will also then put a small bead of RTV around the outline of the old gasket, including the bolt holes."

No, please don't as you will have a mess made of RTV oozing out from around the whole pump gasket surface. The RTV was to be used on the threads of the bolts, maybe 1/4"- 1/2" up the thread, all the way around the bolt, with just enough to fill the grooves, above the lands maybe 1/64"{the thickness of a nail file perhaps, the only thing in sight that's close}. The bolt will thread into the block, and the RTV will seal between the lands & grooves of both the bolt and block threads, set up, and seal the coolant from leaking.
If you put no sealer on the threads, likely you will have coolant seeping past the threads, and out to the world. After while, the threads may start to corrode, and you will have a dickens of a time removing the rusty bolts as they'll bond to the block, and break easier as there is less mass left due to corrosion. They get skinny and rusted in place, and break more readily, using less technical terms.
You would be best advised to use a sharp edge, I use a chisel, to press firmly on the block and remove all the bits of old gasket from the block surface that you are able. Wipe the surface clean, and inspect for 'bumps' of stuff. Remove all you can. You will likely find 'stained' areas where the remaining gasket material is very thin, almost imperceptible to feel, that are very difficult to remove. That's where I stop. Feel the surface for any imperfection, and go from there. That's what the gasket is expected to seal.
Using the RTV to hold the gasket to the pump body would work, BUT, you don't want so much to be there that the gasket gets deformed, nor do you want the RTV to set up prior to installation, as you will again get deformation and leaks. IMO, the most you'd want would be a drop in each flat area between the bolt holes, which would then be spreadable to a very thin layer, almost just a sheen. Then, there would be little to get displaced when you tighten the pump in place.
If you tighten to 120 in/lb, you should be close enough to the spec that there should not be a problem. Do that, wait half an hour or so, and then check that the ooze has not reduced the bolt tension. This is not rocket surgery or brain science, just tightening a bolt. There's a lot of tolerance as long as you do not break the bolt due to over-torque, and do not have leaks due to under-torque.
Doing this stuff can be fun, but it is likely you'll not get your students interested as they all will want to be on-stage somewhere, or on Wall St making a bazillion dollars, or laying on a beach in Cancun sipping drinks or riding a surf board.
tom

 

I have to disagree with Tom. If you don't use RTV there, it will leak almost every time. The assumption that the surfaces are flat or flawless is false. I own several 2.3Ls and can vouch for this.

 

I guess we will agree to disagree. I've been working {ha.!} on cars & engines since 1963, when I tuned up the family station wagon. {Had to use a crowbar on the distributor to get it to move to set the timing, 1st tune in 4 years. A Y-block 292 with the tilted distributor at the back of the engine}
Not too much later on, I replaced the water pump on the 352 in my Dad's T-bird, and did not use permatex {No RTV back then..} and it did not leak. And that is what I've been doing since. The one time I used sealant on the pump gasket surface, I had seepage as the sealant did not allow for a firm, complete torquing of the bolts, slowly oozing out after initial tightening. I tried torquing, and then coming back an hour or so later, and re-torquing. I was not happy with the results. The time I did the timing set on the Vulcan, and I used sealant on the front cover, and found later that the bolts had loosened, or the sealant oozed, leading to slight seepage until I re-torqued the bolts.
From the factory, there is no RTV, only the gasket. I think if you check the shop manual, there is no mention of using RTV on the gasket or surface, except in the case of "T's where block/front cover/pan intersect, or the "V" where the intake transitions from block to cylinder head, or the "L" of the pan gasket where it goes around the corner of the pan to the main bearing cap. All are noted in the manual to 'apply a dab of ...'.
We disagree, and that's fine with me. Your method works for you, so keep it up. I am not so successful with sealants, and find that 'non-hardening' Permatex, is actually hardening, and very difficult to clean from machined metal surfaces when you have to replace the pump a second time. Or third, if you keep a car as long as I have. The Ranger is a 1985, built and bought in 1984, the wagon is an 1987, bought August that year. Ranger is under 80k miles, Sable is almost 250k miles(3-4 pumps). Finally replaced the Lima pump a month ago, and did not use sealant.
YMMV
tom

 

Thank you tomw. Thankfully, I have not even touched the truck because of working. I may have to mess with it this weekend. I've read your response several times.

"No, please don't as you will have a mess made of RTV oozing out from around the whole pump gasket surface. The RTV was to be used on the threads of the bolts, maybe 1/4"- 1/2" up the thread, all the way around the bolt, with just enough to fill the grooves, above the lands maybe 1/64"{the thickness of a nail file perhaps, the only thing in sight that's close}. The bolt will thread into the block, and the RTV will seal between the lands & grooves of both the bolt and block threads, set up, and seal the coolant from leaking."

Thank you - I will take your advice in placing RTV on the threads of the bolts. I did notice that the hole of the bottom bolt looks like it sits in the fluid, probably even when the engine is turned off and circulation stops. When I took the old pump off, fluid gushed out of that bottom hole when I took the bolt out. I didn't know what was going on, but I'm glad you mentioned putting RTV around the bolt at 1/4" to 1/2".

"You would be best advised to use a sharp edge, I use a chisel, to press firmly on the block and remove all the bits of old gasket from the block surface that you are able. Wipe the surface clean, and inspect for 'bumps' of stuff. Remove all you can. You will likely find 'stained' areas where the remaining gasket material is very thin, almost imperceptible to feel, that are very difficult to remove. That's where I stop. Feel the surface for any imperfection, and go from there. That's what the gasket is expected to seal."

I already cleaned the surface with a razor blade. It's shiny and feels smooth as a baby's butt. But I was careful not to cut into the metal at all - I kept the razor as flat as possible. I do see a couple of areas that look as though they are stained a dark gray, and I'm assuming its old gasket material, but I can't get it off and I don't want to bear down to hard on the razor.

Hopefully, using the push tool with the razor blade was acceptable???? Of course, there's nothing I can do about it now anyways.

"Using the RTV to hold the gasket to the pump body would work, BUT, you don't want so much to be there that the gasket gets deformed, nor do you want the RTV to set up prior to installation, as you will again get deformation and leaks. IMO, the most you'd want would be a drop in each flat area between the bolt holes, which would then be spreadable to a very thin layer, almost just a sheen. Then, there would be little to get displaced when you tighten the pump in place.
If you tighten to 120 in/lb, you should be close enough to the spec that there should not be a problem. Do that, wait half an hour or so, and then check that the ooze has not reduced the bolt tension. This is not rocket surgery or brain science, just tightening a bolt. There's a lot of tolerance as long as you do not break the bolt due to over-torque, and do not have leaks due to under-torque."

I will take your advice here too.

"Doing this stuff can be fun, but it is likely you'll not get your students interested as they all will want to be on-stage somewhere, or on Wall St making a bazillion dollars, or laying on a beach in Cancun sipping drinks or riding a surf board."

I teach at a fairly good traditional public school, and the kids do well. I've been at some really bad schools though...its hard teaching biology and physical sciences to gang members! I'm thankful to teacher where I am - many teachers try really hard to teach at my school when there are openings. Teaching sucks, but if you get in the right school with good families and good administrators, it makes a huge difference!

Thanks for your feedback.

 

Another thing I've read is to make sure to NOT overkill with RTV because it can get on that silver ring on the back of the pump and clog it up.