I have recently acquired an X100 4.0 L XKR and I am delighted with it. It starts and runs great, but I am slowly learning about the car. Present question relates to the charge air inlets, the ones with SUPERCHARGED cast on them. After even quite a short run they are very hot to the touch. This the first supercharged car that I have owned and would like to know if these being very hot to the touch is normal. I have not put a gun on them but I would reckon the cooling water in them must be 100 deg C or thereabouts. Thanks in anticipation. Bob

 

Check the intercooler water pump, sort of under the air box. It runs when the ignition is on, no need to start the engine, makes it easier to check. The original part fails, but there is apparently a Bosch alternative. In short, there is a water pump that moves water between a dedicated radiator and these water jackets.

Best of luck, keep us posted.

 

Aware of pump and location. Whirrs away nicely when ignition at position 2. Squeezing discharge hose makes pump noise change so can reasonably assume that it is pumping. Coolant level is well topped up in expansion tank, engine rad and intercooler rad are connected at bottom hose of engine rad just to achieve common fill level, but presumably no flow between (which would be dumb). From what I have read adiabatic compression of the air by the supercharger can raise the temp of the intake air to something like 70 deg C for 25 deg C ambient. Would like some idea of how much I can expect intercooler to cool from 70 deg C. Will try the hand on check of the cold in and hot out hoses to air charge boxes next time I go out, but would appreciate any experience of others. Thanks. Bob

 

There may be air trapped in the inter cooler.Remove the hex plug to bleed.

 

Thanks for the suggestion, have already done that, and 'burped' the system, only coolant moved, no air trapped as far as I can judge.

 

I am sure you cannot go wrong with doing a refresh/cleaning of the cooling fluid, similar to what people do to restore the effectiveness of their heater core in the winter. Over time, the coolant leaves a deposit on all surfaces and it hurts heat transfer. Flush the old fluid, refill with water and a good quality purpose-made cleaner (prestone?), drive around, then flush/refill again with the proper fluid. I have never been clear if the intercooler fluid is separate from the main cooling system so you might have to flush the entire system. As you know, Jaguar used 2 different fluids over the years, and these fluids cannot mix as they can gel. Maybe someone mixed these fluids in the past for a top-off and you are now seeing the consequences. How good is your heater? How far do you have to drive before you get some heat? A clean system should give you some heat in maybe a mile as this was designed as a "low-volume" cooling system.

As you pointed out, there is no substitute for data, some of it will be available over OBDII (intake air temp, manifold pressure, rpm, etc.). I suppose you can also disconnect the pump and check if it gets worse as a data point.

Best of luck, keep us posted.

 

From what I can see strangely the intercooler rad does not have a drain point. The only way I can see to get the old coolant out is to disconnect a hose and apply a bit of gentle air pressure to the filler point between the two air charge chambers and blow it out. As I said earlier the intercooler circuit and the engine rad have a high level connection that I think is just to ensure both systems are filled but does not otherwise allow any coolant flow between them, otherwise the intercooler would run at the 90 - 100 deg C of the engine circuit which is not very helpful. The coolant in the whole system is overdue a change but looks OK and is coloured orange, which I believe is the right coolant for this engine. I have recently finished and engine out refurb of an E type and went into coolants in some depth, would you believe a 50/50 solution has a slightly lower thermal conductivity than pure water, but I do not want a cracked block, so 50/50 it is.

 

Problem solved, or at least plausible explanation. Came in from run and supercharger barely warm to the touch and the air inlets ambient. Left for ten minutes and both supercharger and inlets very hot to the touch. Conclusion water cooling of air inlets working as it should when running, hot supercharger and inlets result of heat soak from large lump of hot engine sitting below, after left standing for a while. Will still be doing change of intercooler and engine coolant as long overdue. Thanks for comments.

 

For what it is worth, on the 4.2l engines, the complete coolant system (including the supercharger rad) is drained from the main rad and then refilled via the supercharger filling port. See below excerpt from the workshop manual.

 

Thanks for that MrTexasDan put an article on the Forum some time ago about how to change coolant on a 4.0L XK8 and the differences for an XKR, he only used the one drain point on the main rad for both models, same as for your 4.2L. Will drain down from the single main rad drain point and check the intercooler rad for any residual fluid and action as necessary. Main thing is to ensure that both rads are refilled on completion!

 

Don't completely commit to this plan. This is a plastic plug in a plastic end tank. If it somehow breaks/strips, you will need a new radiator. If it does not comes off easily, do the drain through the usual radiator hose, or look into the freeze plugs on the block as alternatives.

Best of luck, keep us posted.

 

He will not need a new radiator if that plastic plug breaks. Rockauto sells a replacement radiator drain plug for about $4.26. The brand is Dorman and the part number is 61138. I have replaced mine with this and it's an exact match.
https://www.rockauto.com/en/moreinfo...=12518&jsn=257