Replacing the water pump on my 06 XJR. Should I use RTV on the gasket or just install it dry?

 

I would add some sealer , but I have read some RTV,s have corrosive property's .
If you are using the origenal style o-ring seal I would apply locktight 515 ,
If your upgrading to the flange gasket style you could use 515 or 3bond or even good old shalack .

 

I always use some Hylomar on the gasket when doing a water pump. Great stuff!
Hylomar Universal Blue Sealant - PL32

 

Don't use RTV on a paper gasket. Use spray gasket sealant on both sides of the paper, or use low outgassing RTV with no paper. (silicon poisons O2 sensors and catalysts)

 

If the surfaces are clean, you use new factory gasket and O ring and properly torque the fasteners no sealant is required. None is called for in the service manual.
I did my water pump on my 4.2 NA four years ago and all is well.

 

I personally like hylomar but read it's not the best choice for water pumps...

 

Some gaskets have elastomers pre-applied, some do not. Aftermarket parts with gaskets may appear to have the same shape, but has no elastomer sealant. I would recommend something like Permatex HighTack on any plain paper used on a water pump. (but not the o-ring)

 

Thanks for the answers. The new gasket is made from aluminum and is just under 1/16 inch thick. The water passages in it are surrounded by a rubber type bead. Please see the pictures. The gasket and the mating face of the pump are included.

I was surprised by the gasket thickness and material; it's pretty rigid. Does this change any sealing opinion?

Thanks again

 

Those APPEAR similar to factory parts--where is the O-ring?

 

You don't use anything on the aluminum plate. However, OAT coolant is not to be used with metal impellers. Your pump should have plastic impeller (white poly phenyl sulfide) and use OAT coolant.

 

Once again, thanks. This pump is an ACDELCO and it does have the o-ring already installed. I test fit it and it's fine.

Thanks for the heads up on cavitation. It does have a metal impeller but I wasn't aware of that making a difference.

Oh yeah, (to the original question) , no sealant, cheers.

 

David, excellent catch. The impeller in that ACDelco pump does appear to be stamped steel, which is incompatible with the correct OAT coolant that Jaguar specifies.

My understanding is that OAT coolants provide good protection for aluminum but are antagonistic to steel and solders and do not protect them from cavitation erosion. One reference is at this link:

Engine Coolant Testing

One option is the Airtex AW4124 pump, which has a proper white plastic impeller and is just $32.79 from Rock Auto. Airtex is an OEM for Ford, GM, Chrysler and other major automakers. The Ford Motorcraft pump may also be a good choice. It has the same type of white plastic impeller that looks identical to the one in the Airtex pump, and it is likely made by Airtex, but Rock Auto's price is significantly higher at $115.79.

Cheers,

Don

 

my water pump was an upgrade GMB pump, it does not use the o-ring thankfully as my block was in poor condition were the o-ring mates up , and it has a stainless steel beaded gasket and a stainless steel impeller . i added 3bond to the bead for good measure,
my call is that's a far better option than plastic . pretty shore i read only copper and brass fails with oats and certain cast alloy compounds ? any way I'm having no problems with stainless with oats 25000km's later .

 

After reading the article on corrosion again I decided to return the ACDELCO pump and get the on with the plastic impeller. I emailed RockAuto and explained the problem asking them to basically treat the return as an mis-listed part and asking for a refund plus return shipping. We'll see.

One question, did I read that study right in that the corrosion they measured was over the equivalent of 250,000 miles? I think everything else will fall off before that happens

Either way you guys have convinced me that plastic is the way to go. I've got enough things to fix on this car (I've already been down the 'valley hose' road only to have the EGR to Throttle body hose fail after I replaced it).

Thanks

 

Yes sir and if you want that OATS to keep working effectively, Drain it, back flush and refill every 5 years or 150,000 miles, whichever comes first.

Others may not agree and say based on "personal experience", they haven't had to do that, but OATS has been subject to multiple lawsuits and may now even be on some manufacturers labels. You need only to look at our own Jaguar heater coil issues for examples

Anyhoo, google Dex cool lawsuits and you'll have plenty to read.

You may have already known this, but just in case...

 

The big thing with OAT, you don't want electrolysis. Use distilled water only. Not all OAT's are alike. Use Jaguar, Ford Motorcraft or Havoline Xtended Life. (it deals with the primary additive)

 

Well, thanks everyone for chiming in on this. I spoke to RockAuto about returning the pump and they were unwilling to take pay shipping. They stated the manufacturers claim of compatibility for the part and the fact that the description of the part stated a steel impeller. They guy also researched the issue and found evidence to the contrary, although like you all I found a study that said it offered no protection against corrosion due to cavitation.

I looked up the OEM pumps for Chevy as they have been using Dex-Cool for years and their impellers are steel.

So I gave up and installed it. It went on easy and the thick aluminum gasket worked fine. Time will tell.

 

I bought some oats antifreeze from a ford dealer as it was the one the car was filled from new with and on the back where the mixing details are was a label that had a tap on it indicating that it was to be mixed with tap water so maybe some antifreeze have to be mixed with tap and some with distilled water

 

You should never use tap water in an aluminum engine/cooling system. Electrolysis is the result of electricity flowing through your cooling system and causing an electrochemical charge across the aluminum. This results in rapid corrosion and severe damage to the components in your cooling system including discoloration, pitting, flaking, and pinholes.

 

I installed a metal impeller pump on my 00 S Type & use OAT coolant. Issue free...