Gus or any of the moderators - would appreciate deletion of the previous post (#41) as this covers it. Thanks! Completed!

I completed this last week -perhaps my notes could help anyone else who needs to do this.

As a starting point I used the instructions in the forum from Texas Dan - (pdf with pics) on how to flush the radiator (shows where the radiator plug is and how to remove cover and plug) and Gus's pictures for the t-stat and hose replacement. Thank you both!

1) I bought a 1 mil plastic roll ($3 from Walmart) and spread it below the radiator to catch any leaky coolant
2) Jacked the car up from the front with a hyd jack plus two additional props (tire with wood and the Jag jack) to prevent any safety problems (plus the chock in front of the back tire)
3) Since I didn't need a radiator flush, I opened the valve on the radiator half way (it's on the passenger side and can be reached from the bottom) and let coolant drip into a pan. I figured that way it wouldn't be so hard to put the valve back in.
4) I wanted to drain just enough so that there was no coolant at the t-stat
level; turned out to be about half the pan or equal to one coolant bottle. The coolant was very clean. I started step 5 while the radiator was draining after the level was below the t-stat.
5) There are two electrical connectors CLIPPED on each side of the thermostat. They have a small clip/wedge that can be removed by gently pinching it from the bottom toward the housing. If one pulls too hard, the connector can break.
6) I used a pair of wide pliers to loosen the hose clamps (I pushed them back on the hose so I could reuse them).
7)I dismantled the hoses and the water pump hoses as shown in Gus's pics. I needed a ratchet extension for access to a couple of the 8 mm bolts.
8) To reach the back bolts is a doozy - the 8mm crows foot from Snap-on helps but I still had to shake the housing to get the bolts out.
9) Once the housing is out, I installed the new housing, used the shorter 8 mm bolts from the thermostat for the back of the housing (as everyone has suggested) and reinstalled everything. I added coolant and distilled water and squeezed the hoses to push out any air bubbles.
10) I turned the car on with great apprehension and everything held.
11) Well almost everything - I did have a leak on one of the hoses but it was fixed easily - I just made sure the hose clamps were back exactly on the same bumps as before - otherwise the coolant can bubble out.


Again thanks Texas Dan and Gus


__________________

 

I had a leak somewhere in the thermostat housing area so I decided to replace the plastic housing with an aluminum kit. I replaced the thermostat and also the gaskets on the water outlet pipes also. I purchased the 8mm crowsfoot from snapon and it worked on one side of the rear housing bolts. I had a problem with second rear bolt and it started to round out from the 8mm open end crowsfoot. Had to get a flare nut 8mm crowsfoot to get it out. Unfortunately I had to buy a whole kit to get the 8mm flare nut wrench. So far so good and appears to be no leaks. I could not identify exactly where the leak was in the old plastic housing but noticed there was one nut in the thermostat housing that had spun and the bolt could not be tightened. Appreciate all of the tips which in total helped me get the work done.

Jim
1998 XJ8 (70k miles)

 

I had a leak today in the coolant system and I replaced the water pump and crossover pipe. I found a crack in the crossover pipe about 3” long. I will post a photos and procedure soon on my page.

 

I found that a 5/16 crowsfoot worked better. And its a lot cheaper

 

This is a regular problem with the cars. Jaguar manufacture the damned things using a form of Bakelite, which is the original 'thermoset' plastic invented 'way back in 1908. Even 'modernised' it suffers from aging which is aggravated by heat, just the same as when it is used in electrical fittings. (Like light holders, switches etc). Not only do they get brittle, but they also warp, which results in a small but steady leak which is often not obvious for a long time as the heat of the engine evaporates the coolant before it reaches your garage floor. They can then fail (apparently) suddenly on the road, and do a fair bit of engine damage if you don't happen to spot the waring light in time.

Go to an 'Indie' and get the aluminium aftermarket replacement thermostat housing: they are a vastly better product and will last much longer. So far, it doesn't appear that there is an aluminium substitute for the flow crosspiece.

Cheers,

Languid

 

p.s. A strong recommendation - DON'T mix different brands of coolant. 9 times out of 10 you will get away with it, but equivalent doesn't mean identical. Different manufacturers use different chemical formulations, and if you get the wrong resulatant 'recipe' through the mix, you can get 'sludging' which can result in you having to carry out a full flush of the system. Too much like hard work to save a few cents for me.

Cheers,

Languid

 

Not necessary to remove the intake. One quick blow with a hammer and chisel and that old brittle plastic stat housing will split into two like an eggshell giving clear access to those little 8mm bolts with a box wrench. The old part is junk anyway, so who cares? Mine was so brittle that the neck portion under the little cap broke off when I tried to snug it down by hand after I heard it hissing and smelled coolant under the hood. When installing the new part, use the 2 shortest bolts and simply cut a slot in the top of them with a hacksaw which will allow you to run them in using a long, thin flat blade screwdriver. These bolts don't require a lot of torque anyway if you use a new gasket and grey permatex. The whole job took me less than 45 minutes and I replaced the thermostat as long as I had it opened up. There's more than one way to skin these cats.

 

Slug,

Yup, thats the plastic (bakelite).

jrb57 - that'd do it. probably because someone tried to stop the leak in the first place.

As for the difficulty of accessing the bolts, (my field is electro-mechanical engineering) there are times when I think that as part of their education the design engineers, a compulsory 12 months in a workshop doing practical repair work should occur.

 

I just ordered the kit and I noticed it does not include any bolts
JA-AJ8-2217KIT - Alloy Housing Thermostat Housing In Alloy, 4.0 V-8

I guess I will be reusing the old bolt. All of you guys are saying use the Tstat bolts to mount the back of the baseplate. I guess that means reuse the old back-bottom ones on the thermostat?

p.s. I work at a hardware store so I think Im gonna buy every 8mm bolt we got. Gonna get an 8mm wrench too and have a welding shop down the street bend it.

 

I just added the R&R of my water pump and crossover pipe on my page JagRepair.com - Jaguar Repair Information Resource due to a leak.

 

Based on tips from others I changed out the two back thermostat housing bolts for two of the shorter ones on the thermostat cover. I reused the longer bolts on the thermostat cover without any problem so far.

jrb57
98XJ8 (70k miles)

 

Slug - You are THE MAN! I had to replace my thermostat tower, and removing all of the other elements was fairly easy thanks to all of the previous contributions and instructions from Gus and others - truly, truly appreciated. Bottom line - the hammer and chisel approach made removal a 'snap'. Literally. The only downside: I've got a 'virgin' 8mm crowfoot sitting in the garage, compliments of Matco Tools. Sigh. Perhaps I'll need it for re-attaching the tower.

The replacement aluminum housing + new thermostat are due to arrive tomorrow. The nifty short-bolt swap trick is top of mind.

 

I found that the 5/16" crowsfoot wrench will work on the 8mm bolts.
It costs a lot less and is available in most SAE wrench sets.

Although I did like the solution of cutting a slot in the top of the bolt heads to tighten them up using a screwdriver when replacing the coolant tower. By all means get the Aluminum replacement tower.

I did notice that my "Coolant Low" alert comes on when the Oil gets low.
Could not get the oil cap off because the engine was hot. So, I poured
the oil in via the rebreather tube back to the valve cover. I didn't get the
"Coolant Low" alert anymore. Odd way to indicate the oil is low.
I checked the coolant later and it was not that low.

112K miles on the 1999 VDP and still looking good and riding great!

 

Guys - I changed out my plastic crap thermostat housing for the aluminum upgrade on my 00 S Type - Regarding the 8m crowfoot dilemma - Here is a better and more available option on www.amazon.com - 8mm flex head ratcheting spanner wrench - $14.24

No need to cut into the bolts to get them started - this wrench was a godsend compared to the 8mm crowfoot wrench due to the self ratcheting function...

 

Wrapped it up in short order tonight. The box-o-parts was waiting for me when I got home from work, and putting it all back together was a snap. I did wind up using a hacksaw to put a slice in the top of the two short bolts used in attaching the rear of the thermostat housing. It sure made a lot less work on the crowfoot, which worked, but...I wouldn't want to spend a lot of time cranking on that thing.

Think I'll toss a couple of Advil down the gullet and see if the Mrs. wants to work a few of the kinks out in the lower back for me.

 

Here is an inexpensive crow foot in 8mm for only $2.86.

V8 Tools 74008 3/8" Drive Metric Crowfoot Wrench - 8mm


Happy motoring

 

This may seem like a dumb question, but do the torque requirements increase when switching from a plastic housing (bakelite) to a metal housing?

 

It shouldn't. The bolt is being tightened down just enough to compress the rubber seal.

It's not really a torque wrench problem.

 

This is to FactoryJaguarTech on JagForums. I was looking at a post about a leaking thermostat tower and noticed that you mentioned that - "If need be, I will do a how to on removing the intake. " on the X308 engine. I'm faced with this now so I'm wondering if you ever got around to doing the writeup? Also does the large round plastic piece on the front of the intake housing come off in any way - it sure would make accessing the thermo tower inner bolts easier. If not we';; have to stick with the old harder, tedious way.

Thnaks, in advance. My email is: alphajag@att.net