Cooling system

[sKrazo]

Noob question here:

I'm starting to work on my XJ more & more. I replaced the t-stat couple weeks ago. It went just fine. I realize this is prob simple for most but it was big job for me. Anyway, I used red rtv to seal the felt gasket, it was only way I could get it to seal. I waited 24hrs to refill coolant so rtv could setup/cure. Well now my radiator has a slow leak. Could be coincidence, my 2001 xj does have 125k miles. I'm planning to replace the radiator this weekend. I plan to do the water pump at the same time. I'm concerned about getting the water pump sealed without rtv. Could the rtv have caused my radiator to spring a leak? Is this a no-no? Any suggestions?

Also, anything else I should consider doing while I'm working I there? I may replace the serpentine belt too, what about the fan clutch? It seems to work just fine now but if I'm there I was considering it too.

Couple years ago I put a Hayden tranny cooler on too. Noob mistake, I mounted it in front of electric fan. I'll prob relocate it in front of radiator fan.

[Mudderoy]

Getting the thermostat housing to seal should be pretty easy. You need to make sure both surfaces are clean of all old gasket/rtv. Instructions on the RTV are something like 30 minutes (read it, I don't remember). I never wait that long. I just put it on there then line everything up and bolt it down.

If the thermostat housing was leaking before, fixing that leak could have caused the leak to move to the next weakest place, like the radiator.

[4.3LXJ]

Lots of questions there. No you did not make a mistake with RTV. Very common use for it. It will not cause a radiator leak. Before you replace it, flush the system then remove it. Check the fan clutch by rotating the fan with the engine off. If it is stuck or has resistance but rotates, it needs to be replaced. And yes, the tranny cooler needs to change sides

[Carves]

Moving the oil cooler is a good idea. If its in front of the clutchfan - its always going to get fan forced airflow.


Thin smear of RTV on both sides of the gasket - ensures a good seal.
It also helps seal - if you have a bit of pitting in the metal ... like in this t'stat housing.





Dont tighten down on it too much tho ... as that just squeezes it all out ... so definitely let it cure a bit as you're aware.

Use it on the waterpump too.


Not uncommon for an old radiator to show its faults, after being disturbed while fitting other parts.

Dont forget the rad mounts probably need replacing too.





125k ??? ... I'd bang a new fanclutch in regardless.

Besides its a much easier job when all the junk is out of the way .. even if you do have good help ..





Ignore where stuff is located ... Its a RHD.

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[sKrazo]

Thanks guys. I feel more at ease using rtv on the t' stat as well as on the upcoming water pump replacement. I'll check the fan clutch but more than likely I'll just replace since I'm there. Also appreciate the tip on the radiator mounts. I'll pick those up just in case I need them as well. I'll try to post some pics as I go. Plan to start on it Saturday morning.


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[XJ Wheeler]

Another part to possibly replace is the inlet tube. It screws into the top left of the water pump (facing the front of the engine). Often it's rusty and none of the replacements water pumps I've seen come with it. Check yours out and see its condition.



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