I've decided to install temp sensors in each of the thermostat housings, and today I got around to draining the coolant and pulling the housings off.

The right side was uneventful. The left side was a shocker (to me at least)...

When I pulled the upper radiator hose away from the housing, something with the consistency of thick pea soup drooled out of the housing. When I got the housing off, more of this stuff came out. I was surprised at the thickness and color of the stuff. It was somewhere between green and brown. It was dramatically different than what came out of the right side.

I just got the car last August, and have little idea of its history so I don't know if the coolant is 6 months or 10 years old. When I drained the radiator (what a PITA by the way...) it didn't look all that bad...which only added to my surprise of how the goo wouldn't have gotten diluted by the crossover pipe. Maybe it's blocked?

Anyway, comments would be appreciated.

Thanks!

John
1987 XJS V12, 62,000 miles

 

Hmmm.

I'm not sure what the goo would be but you'll obviously have to determine how widespread it is and make sure it is eradicated. Might be a good time to remove the radiator and have it professionally cleaned.

With the thermo out you can probably see into the coolant rail for inspection.

The radiator is partitioned...or I should say partly partitioned... so it's not too unreasonable to have the one half of the cooling system look and perform differently the the other side.

Cheers
DD

 

+ at least 1.

Radiator out and professionally cleaned is now mandatory in my opinion.

Never seen green goo, brown and black, yes. Sounds horribly like radiator sealant that has been added previously, and that stuff is dangerous in any car in my opinion. If it leaks, FIX IT.

With the thermostats out a reasonable flush of the block is possible. Time consuming, frustrating, messy, YES, but do-able.

Do not forget to flush the heater core, both ways, as that is a known storage facility for gunk.

Lots of things need checking now you/us know of this gunk.

1) The banjo arrangement on the RH side of the radiator is a must.
2) The small pipe unit across the top of the radiator panel is a must.
3) The heater hoses from the RH head to the tap, and then to and from the core are also in need of cleaning, and /or replacing.
4) The metal pipe running down the LH chassis rail (heater return) will need flushing also.
5) The metal header tank in the LH front corner of the engine bay will need removing and flushing. It will be full of gunk.
6) The atmospheric tank in the LH wheel arch panel will be full of mud also, so removal and flushing will be required.
7) All the small coolant hoses associated with the cooling system should be replaced.

 

Well, the photo says it all I think.

Spent a good part of the day pulling the radiator. Surprisingly, I really didn't find any of the pea green/brown gunk in the left side thermostat housing or pipe...but it all gets cleaned/replaced anyway. Now to find a good radiator repair shop...

For laughs I pulled the heat shied (which I intend to clean, prime and paint) and was surprised to find that the rear heat shield bolt hole (not in the photo) appears to go all the way into the exhaust flow judging by the amount of soot on the end of the bolt. Why would this be? Not a big deal, just curious.

Thanks,

John
1987 XJS V12, 62000 miles

 

John, glad to see you are having fun.

That shield bot from memory (not as it was) I reckon was a blind hole???, but if it goes thru it sounds odd to me, even for the British. maybe something to do with EGR (exhaust gas recirculating) that we never had down here.

 

New here to the forums, new '89 XJS owner, so excuse some of my ignorance, please.

So the V12 XJS has TWO thermostats? My car was overheating, and having experience working on cars, I knew the symptoms were pointing to a stuck thermostat. I changed a thermostat on the driver's side, noticed that there were two upper hoses coming from the radiator, and started to wonder if it may have two thermostats.

And in case you are wondering, the thermostat I changed was indeed stuck closed. If it does indeed have two, I guess I got lucky and happened to change the correct one, as the car stays nice and cool.

Eskr

 

Yes it does, one on each side of the V in the mirror position of the one you, luckily, replaced!

Good plan to download Kirbert Palm's book on the XJS, it is a great way to get started on understanding the car.

Welcome to the automobile elite!
Greg

 

Hi ESKR,
Welcome aboard this forum, you'll fins a very good resource for tips, how-to's and problem solving by some excellent members. Please don't be a stranger, and feel free to comment, ask questions, and especially post photos of your XJS.