HI All,

Ive tried to search the forum for answers but had not much luck.

Iam new to the xjs, my 1st one and Iam still trying to find my way around it.

so took my son (9) out in it the other day, he was begin to like it and
the xjs 4.0 celebration just stopped blowing air.
also the fan kicks in after a few minutes. ( which i can live with).

need to revive his interest in it, and as it cold here in the uk, i need to sort the heating problem fast.

ive checked the heater valve, which seems to be rusted, so have ordered a new one, not too bad at £40.

but i was just checking and don't seem to much suction from the small pipe that fits into it. how can i check this and if there is a problem how hard is this to fix?

and any pointers in the right direction would be great.

or if anyone can physically help too, Iam based in west london, uk.

thanks

 

You can pop a vacuum gauge in the output to the heater valve. That will give us some data to address.

Anothe optionn is to just connect the heater valve valve to the plenum vacuum taps. That should open the heater valve.

edit:Wrong! Backwards! Reverse that. That was my summer fix. As Doug correctly says below. Posting after work is fine. After drinks may be questionable.

I am am totally open to helping you sort 'this out personally. I'm in North Carolina USA but a simple ticket and lodging and I'm there. we'll get her sorted!

 

The 'could be' list might get a bit long.

But, if the heater valve is faulty, replacing it *might* solve the "stopped blowing air" problem.

If heat is called for the system will not let the blowers operate until or unless sufficiently hot coolant is reaching the heater core. This is determined by a small heat sensor on one of the pipes to the heater core/heater matrix. If the sensor doesn't sense hot coolant, the blowers will not operate.

A stuck-closed heater valve would prevent hot coolant from reaching the heater core....and thus the sensor will not pick-up a heat reading.

This can be checked by calling up full cooling on the control dial. If full cooling is asked for the system disregards the reading from the sensor and will let the blowers operate. If the blowers remain inoperative in cooling mode then there's a different problem


The heater valve opens when no vacuum is applied. It closes when vacuum IS applied. So, it is normal that you would not feel vacuum if the system is in heating mode.....or blending mode, for that matter.

When the system is in full *cooling* mode vacuum will be applied to the valve, closing it.

Cheers
DD

 

tajsingh,

On a late XJS like yours, the blowers do not operate for a couple of minutes after startup unless you set the blower to defrost mode. It's quite normal.

Paul

 

You should be able to close the heater valve by hand if it is stiff or you can not move it then this is your problem, I replaced mine with one from a late GM car.