www.jec.org.uk

Dear All

Those of you who read my post on our recent trip to Scotland will know that we had a couple of instances of the temp gauge creeping over towards the red - in heavy traffic and when using the air con under high ambient temperature conditions. At one stage we had to open the windows and turn the heater on to full hot to keep it under control.

I diagnosed this as a rad problem and knowing how bad the rads in the XJS can get coupled with my own hatred of cars overheating decided to replace it (I think there are few worse things than sitting in a jam watching the temp. gauge gently creeping towards the red).

Net research showed that the original fit rads were available (again?) from Jaguar part no. JMHE4190AA, retail £375.00+VAT, £309.88+VAT after JEC/Jaguar Allegiance discount. I opted for this route on the grounds not only that OE fit is always a good option, but also it avoided the car being off the road for days whilst the rad was removed/re-cored/refitted.

The work was done by my regular garage, Swallows Jaguar in Somerset who also fitted new o/s/r hub carrier fulcrum bearings (these were the source of an annoying clonk when engaging reverse and turned out to be seized solid (oops )

Heres a pic of the old rad complete -

Initially I was disappointed as to how good it looked and wondered if I had wasted a lot of money - however

there are clear signs of deterioration here at the bottom corner and on the other side here

I could push my finger straight through the cooling fin material between the tubes - it was rotten!

More importantly I think, Swallows told me that the old unit was significantly heavier than the new one, indicating that it had nearly 100K miles and fifteen years worth of accumulated crud in it.

The temp gauge needle had always sat just to the right of the 'N' and recently would get halfway to the red with little provocation.
Since the new rad was fitted it sits squarely on top of the 'N' and I have been unable to provoke it to the right so far despite the hot weather over the past couple of days.

In summary then I think the money was well spent for peace of mind and engine protection. Although a significant cost to purchase, over the life of the rad I don't think it's too much to pay and you could always fit it yourself - I've given up on that now!
With summer here if you find your own temp. gauge creeping towards the hot zone perhaps you need a new rad too?

Best Wishes
Tony

Top job Tony !


are you going to get the old rad recored ? its about £100 aint it ? , then you could sell it on and get a little money back , or just keep it as a spare ?

by the looks of the outlets, your rad also cooled the transmission fluid.....



BB

Well done!

I too have just had a new radiator. The genuine Jaguar item and a new genuine Jaguar thermostat were fitted by the local main dealer.

However my experience is the exact opposite. The temp gauge, which has always sat rock steady on N through three previous radiators, now makes its way up to almost halfway to the red and then drops back down to just above N over a ten or fifteeen minute cycle. It then repeats this process.

I strongly suspect the Jaguar thermostat but at £30+ a pop am in no hurry to get another just to see if I can do a better job than the main dealer.

This link sums things up under the circumstances.

http://www.youtube.com/watch?v=Cb2kBFqr ... re=related

Heat is work and work is heat!

Mike

Vince
Did I miss a trick re the old rad? - I left it at Swallows, tho' I could have brought it home, I didn't want it. Somehow I doubt if you could get it re-cored for £100 - I should think the new core itself costs at least that - my guess would be nearer £250 plus the dreaded, but if anyone has had a rad re-cored recently do let us know.
If anyone wants the old unit to recore for themselves it will still be there with the box etc. from the new one and I'm sure they will have no objections to you having it.

You are correct in spotting the auto box cooler inlet/outlet pipes, another good reason for a new rad as this assy. is retained on a re-core.

Almcl
If you had those new bits fitted recently at a main dealer I'd be back there first thing Monday morning banging on there door! Surely you pay through the nose for a proper service and the associated warranty don't you? If it ain't right - and I think you're correct in your diagnosis of a faulty thermostat - it's down to them to make it right, irrespective of what it takes.
Just my two-penneth worth

Regards
Tony

a ' re-core ' of a radiator shoulnt cost more than £150 , but then again it all depends on the type of core they solder back in ,

i would imagine your old rad would have already been done by now Tony , as you left it there, lol

did you get the transmission fluid changed , or just top it up after , as i expect you lost about half a litre in the rad swap-out ,

my V12 rad also cools the auto transmission fluid , the power steering has its own little cooling radiator under the engine ,

i was lucky in that i found and fitted a new rad to the V12 several years ago along with all new hoses and stats ( x2 ) , i have also converted to electric cooling rather than the antiquated viscous fitting, which meant modifying the front of the engine and pulley system to do away with a fan belt and pulley mount , this also meant installing a separate thermostat to control the electric fan ,

this also free'd up a few horses, as the viscous fitting is no longer sucking power directly off the engine , lol

BB

Almcl
If you had those new bits fitted recently at a main dealer I'd be back there first thing Monday morning banging on there door! Surely you pay through the nose for a proper service and the associated warranty don't you? If it ain't right - and I think you're correct in your diagnosis of a faulty thermostat - it's down to them to make it right, irrespective of what it takes.

Tony

I suspect they would claim it IS right as it doesn't go out of the normal zone on the gauge. This zone was enlarged according to the 93 model year data (below) precisely to stop customrs complaining:

http://www.almclwebpages.pwp.blueyonder ... pgauge.JPG

They took it for a thirty mile test drive after the work so one hopes they saw the performance. Now they will claim it is standard.

almcl

Ah, I understand, my gauge is the same as yours with the white enclosed range. However it didn't really reassure me as the needle progressed across it to the top of the "normal"!
In any event, as your car seems to be performing within the specified parameters after a thirty mile road test I guess they must be happy with it.

I did pay particular attention to my gauge this morning on the way to work and it too shows signs of "cycling". However, the range is only about three mm from the centre of the "N" to the right side of the "N" and the cycle seems almost continuous ie about thirty seconds.
Perhaps your stat. is a bit lazy?

Regards
Tony

Tony

Yours sounds just like mine used to be!

Agreed, I too think the stat is lazy, but controlling. My IR thermometer suggests, when pointed at the 'stat housing, that the temp is around 90°C

It's a bit hard to check for certain, say going up a sustained hill at speed, when the temp does sit midway between n and red. It's going to get a work out next week as we are off on the Entente.

I did take it for a run round Shropshire early the other morning: 115 miles in 2 1/4 hours and although it wasn't particularly warm (22°C) it was moderately reassuring.

I had my radiator re-cored but my thermostat is stuck open and I cannot get the needle to rise to midway no matter how hard I thrash it (it is a manual!).
I have checked the viscous coupling and it is working fine i.e. allows fan to idle when the revs are increased.

I will sort the thermostat in the next month or so but even in this recent hot weather, with the air conditioning on and driving like a launatic the gauge would not go near the middle, but stayed around 1/3 from cold. I guess this shows that for a 4.0 the coolant system is more than adequate for this country.

Tony,

As you know, the late 4 litre auto rads also cool the autobox. Having that separate section obviously makes it more expensive than a standard rad.

You probably saw my article in the mag two months ago about my own rad problems. I went for a recore job. The prices for a decent recore for the late rad varied from £210 to £300. I paid about £235 for mine.

My gauge now doesn't rise above mid-way with aircon on and sitting in traffic in the heat. I do get very minor variations in gauge deflection as, I guess, the thermostat peiodically opens. However, the changes are miniscule and all occur at exactly the mid-way mark on the gauge.

The other thing that causes gauge variation is the sender unit. There are two types - black end or red end. Some specialist dealers don't seem to care which one they sell to you but it's important to have the right one for your year of car.

Paul

Reading back though this thread, it seems like the official Jaguar line is that the normal temperature is pretty much anywhere on the gauge.

Surely that can't be right?!

Tell that to a V12 owner, it will let go before it ever gets near "H"!

I recently replaced my thermostat again after the needle kept wandering about with the previous replacement and the needle now sits on "N", no amount of kickdown, steep hill, aircon or even all three can get it to move more than 0.5mm to the hot.

Well, after 1600 miles on the Entente Cordiale last week, I haven't noticed any problems.

The gauge was up above the N when cruising at motorway speeds or when ascending the alpine bends coming back from Switzerland, but stuck in traffic (happened two or three times) it dropped back down to just below the mid-point of the N. This makes me think that it may be a different issue: one of circulation restriction at high engine speeds. Traditionally, I known this is more of a V12 problem, where hose collapse can occur when the water pump runs too fast for the flow capacity of the system.

But I haven't thought of a suitable way to test this hypothesis yet.