My 1999 xj8 mainly blows cold when on the highway and doesn’t blow full blast too great. Where would be a start in improving the air flow velocity and volume of air being pushed out?

when I first got the car the AC would blow out little pieces of foam/particles out of the vents. Is it possible the vent tubes are clogged up and is it easy to take apart the venting?

 

I believe it was Vauxi, one of our members here, that had that same issue. As I recall he reported that he
vacuumed the foam from the fans and vents.

 

https://www.jaguarforums.com/forum/x...r-time-223146/

Seeing it’s the same year as my old XJR, check out this post.

 

Yes I have vacuumed foam of the both blowers. Evaporator in the link has a lot of plant growth accumulated to it. I'd bet that AC has been smelling very bad for years. To clean anytring else from the foam than blower motor wheels, you have to take all apart as in link. Foam that comes off from those recirc flaps is very fragile from age and practically crumbles when touch. So if those pieces of fome has gone through blower and heading to the evoparator cell it will not block there anything.
My issue was noise from left blower motor. Where foam was unbalancing it.

 

I've just removed the center dash vents to repair the piece that the wood trim clips into (worth a separate rant!) I'd noticed the little foam pieces and heard some noises as well. I found the foam source (I believe) to be the flaps just behind the vents so I don't think it has much of a chance of plugging anything. Probably have to dig in a little deeper to get to the source of any real restriction or smell generators...

 

The engineers could have prevented this malady by covering the foam with a thin material.
It is good that we are now aware of this issue so that it can be addressed when the need
arises. Also, that we know the depths the condition can sink to which might require extensive
removals of affected parts. I am uncertain what conditions would promote the growth in
the evaporator to the extent shown, however I am sure I do not wish ever to be required to
address that.

 

Foam can not be covered with anything as the foam is acting as noise suppressor. Whining and other air movement noises like that. Couple years ago I replaced my winter beater Volvo heater core and while I was there looked in to the flaps(deforster, floor etc) just to make sure how they move after all of the 24years of driving. Flaps used to be covered with the foam. Only glue residue was left. I like to make jobs done great so in that in mind I replaced the foams. I surely dont think that the modern stuff will stay there next 15+ years. But it is done now. And if ever I have to take xj heater assembly out of the car, I'll do the same thing. I hate whistling sounds from the heater or windows..

 

I suspect that a thin nylon reinforced netting would sufficiently reinforce the foam such that it would
not disintegrate and dislodge itself into the internal workings of the unit. while retaining the noise
suppression intended. In your case, with no foam being present at all, I am certain the difference
would be noticeable. Good engineers design equipment to last the anticipated life of the car.
Better engineers design equipment to last.