Hi there I have 2004 jaguar xjr and I recently changed the coolant hose that goes under the supercharger. So I got that fixed and that required for the supercharger to come off in order to get to the hose. Now I have the car back and running properly the only odd thing I noticed is that my cooling fans stay on while the car is at normal temp and I noticed that the car has lack of power when i floored it going at highway speeds I didn't notice a difference when I floored it going 30. The car did loose all the coolant while that happned. Can someone please help out I've been searching for a solid answer but I can't seem to find one much appreciated thank you.

 

You have possibly got an airlock in the cooling system, the system needs to be properly bled, if the coolant temp sensor doesn't get immersed in coolant, it can't read the temperature of the coolant and the ECU will activate the cooling fans. Another possibility is that when the supercharger was refitted the gaskets have not been fitted properly and could be causing a blockage, which again will give a false temperature reading and active the fans. This might also possibly put the car in Limp mode, or if the supercharger wasn't seated properly, result in a lack of boost from it

 

oh okay makes sense. Another thing that I saw was changing the coolant temp sensor might that help out in my situation with the whole cooling fans being on? I'll get back to my mechanic about the supercharger being placed back in properly thank you so much for the info.

 

When you lost all your coolant did you stop the car right away before overheating?

It is rather difficult to not seat the supercharger properly when re installing. If that were the case then the charge coolers would be very difficult to mate up with the "spreader" that guides air from the supercharger into the charge coolers.

What it could be, among several possibilities, is the super charger bypass valve may well not have been re installed properly. It is quite tricky to do if one
has not done it before.

This is easy to do and if so will cause lack of power as the SC will be bypassed constantly.

If the proper coolant top up process was not followed then you could easily have air in the system.

 

My wife was driving it when this happned I couldn't answer the phone when she called so she drove to the nearest exit approximate 15-20 min tops then she said the car just stalled and wouldn't turn on right when she made it to the exit. It was a very snowy day that day so she was going under 30 m.p.h

How can I get rid of the air in the system ?

and what did you mean by this is easy to do ?

 

I meant that it is easy not to hook up the bypass valve properly so that it prevents the super charger from functioning properly. Will not cause any damage.

To top up the coolant after it has been drained you are supposed to have the heat on full when you top up the coolant reservoir.

You do this before the engine gets hot otherwise you could get burned with hot coolant.

Also there is a top up plug that can be used for the final "cup" of coolant on the top next to the RH charge cooler.

Also many swear by having the front of the car higher than the rear when doing this.

 

okay gotcha . So I did mention the car did go like 20 min running without any coolant should I be concerned about any future problems if so would you recommend just selling the car before I have to do more repairs on it.

 

20 minutes running without coolant is long enough to possibly cause warped heads.

If it was a relatively slow bleed out maybe not. It sounds like it was at least cold out.

If the heads are warped you would be losing coolant at some spots around the mating surfaces of the heads. That could be clouds of white "smoke" out the exhausts and or milky deposits in the oil.

If neither of those things are happening then you might just be lucky.

Do you have any warning lights on or error codes?

 

sorry about the late reply. And no it's not smoking at all I've had the car for about 4 days since the fix and I also haven't seen any loss of coolant at all,also I don't have any warning lights on the dash.

 

Ah ok, there is a strong possibility that you have blown the head gaskets, or at least one, or warped a head or 2. The fans being on will more than likely be due to low coolant level, it could even be low by just a few cups, I doubt that the temp sensor has gone. but it's a fairly cheap part and no harm in changing it if you suspect it.

As Jackra says, The loss of power could be blown head gaskets/warped heads, but if you are very very lucky, then the bypass valve sound like a very plausible possibility, I have never worked on one of these engines so have never had the pleasure of removing and refitting a supercharger.......yet.

I hope you have been lucky and it's just low coolant and the bypass valve, but I think you should be prepared for the worst. It's highly unlikely, no matter how cold it is outside, that an engine would run for 20 minutes with little or no coolant and not suffer blown head gaskets and warped heads.

 

Ok as brian5 stated warped heads are still a possibility however I would go thru the coolant top up procedure to eliminate any air pockets for now.

Also there are lots of connections at the rear of the SC however if one of those connections was screwed up it would likely lead to an error code which by the sound of it you do not have.

The SC bypass valve, if not connected properly, will not give an error code.

The car will drive like a normally aspirated car but with less power due to the significantly lower compression.

IF it is the bypass valve it can be accessed relatively easily once the aluminum intake is removed.

The SC bypass valve you can see in the pic with the black dome and vacuum hose coming out of it. Forget the red tubing that is my pressure take off for water/meth.

I have been thru this so that is how I know.

There are pressure tests that you can perform to see if you have a blown gasket due to warped heads.

However no white smoke, clean oil, and clean coolant are all good news.

 

Where can I locate the coolant temp sensor I can't seem to find it on my car.

And I only feel the loos of power going at highway speeds but not at launch or going 30. I did only once do it on the highway since I got the car back 4 days ago I'll try it again tonight after work and see if I see a difference.

 

How would I know if the bypass wasn't properly put back together ?

Also would I have seen white smoke ,loss of coolant by now since I've had it for about 4-5 days since the fix and my oil also seems okay nothing abnormal no milky stuff in it

 

Yeah, Thanks Jackra, I meant to say to go with a coolant bleed first off, always work up from cheap to expensive, LOL

 

The easiest way is to measure boost. If you are not getting sufficient boost at say 3,000 rpm that would be an indicator.

I believe the coolant sensor is in the pic on the back of the branch thermostat housing.

 

would you recommend on just buying a new bypass vale.

thank you for all the help it's much appreciated

 

No.

The bypass valve is unlikely to be damaged. If it is not installed correctly it is a relatively easy fix if somewhat fiddly.

It is vacuum operated and has a metal rod that actuates a butterfly valve. It is the metal rod that is fiddly to reattach properly due to a very confined space.

It is also easy to drop a nut that attaches the valve body in place and once dropped it is difficult to find. I do it with a paper towel underneath to catch the nut.

 

okay so I need to take the intake of in order to do so or can it be done without taking the intake of?

 

You have to take the intake off.

 

Two pics showing bypass actuator removed and the nut screwed on the bolt, that holds the actuator in place, to keep safe. The first pic is from the side.

The other pic shows the bypass actuator in place .
A metal rod protrudes below the actuator to operate the butterfly and is moved up and down, the rod that is, by the pressure pump.

The second pic shows the inlet/outlet from the "spreader" attached to the top of the butterfly valve. Looking from the front.

Apart from the nut holding the actuator bracket in place there is also a small protrusion that slots into a corresponding hole that aligns the bracket in the correct position. all of this once the metal rod is hooked into place on the spindle that operates the butterfly valve.

That "spindle" is the flat metal piece you can see just above the nut housing in the 1st pic. It has a hole on the end into which the metal rod hooks.