ZX 1.9TD 1996 Waxstat, coolant and sunroof

cdbe · Post by **cdbe** » 05 May 2010, 21:38

I have recently bought the above car and I am slowly working through some minor and major repairs. The main one being replacement of the dreaded heater matrix - only took about 15 hours!!.

I would now appreciate advice on the following:

Waxstat - this is working (fast idles at 1100 rpm when started from cold then drops to normal tickover) but takes ages to do this - up to 3 miles of driving. Is it worth replacing - I am assuming it has hardened with age which is why it takes so long to warm up, I am tempted to disconnect it but don't know whether it does something else to help the car start/warm up.

Coolant - renewed following matrix replacement, bled as per Haynes manual with temp header tank etc, temperature gauge needle always goes up past the mid line between 60 and 90 (I presume this is approx 75 in which case I estimate it sits around 80 and stays there in normal driving but is not completely stable - I am hoping this is just a response to the thermostat opening and closing and not air in the system? in slow traffic it rises to just above 90 before the fan kicks in and cools it down.

Sunroof - tilts but does not slide, I have not investigated yet but any suggestions would be appreciated.

Thanks.

Sl4yer · Post by **Sl4yer** » 05 May 2010, 22:48

Waxstat - sounds perfect!

Coolant temperature - sounds perfect!

Sunroof - doesn't sound perfect. The only problem I've ever had with mine was that the wife wasn't pressing the button properly...

James

Chlorate · Post by **Chlorate** » 05 May 2010, 22:58

Agreed on the coolant stuff, sounds about right...or at least I hope so, is what my car does

.

My sunroof does that too, it used to open all the way back but it stopped. I'm thinking it got stuck because of a combination of a bit of corrosion and the little plastic "thingy" that stops the car becoming a giant whistle had broke loose on one side and possibly jammed.
One of those things I've been meaning to look at "when I get around to it". Otherwise no idea about how to free it up.

-Alex

Dommo · Post by **Dommo** » 05 May 2010, 23:02

The waxstat is definately supposed to do that, it basically does it until your coolant is up to temperature and the thermostat opens. If you look where the waxstat is, it's in the same place as the thermostat.

handyman · Post by **handyman** » 08 May 2010, 06:02

Your sunroof problem could be one of three things.

1. Incorrect operation of switch. Tilt facility is the opposite of the glass opening and sliding back. Press switch as for closing the tilt and keep holding down. Motor should keep running and drop glass down and slid back.
Surprising how common this is!

2. Worn brushes or armature on motor.

3. Worn guide tracks or actuator on cable. Does the glass sit pissed in the roof hole?

H

spider · Post by **spider** » 08 May 2010, 11:43

I'd agree regarding the wax stat. You can do away with it (actually the XUD9 406 has the same thermostat housing but a blanking plug in there. Its actually the same size as the rad fan aperture), but if you do do away with it you will regret it as it will try to idle at about 600 rpm when cold and be prone to cutting out on decelleration, at least until its got a bit warm.

I used a Renault one in my 205, as it expands quicker, although the cable is short so may not fit yours. I do not think you have a problem though really, as long as the cable does actually release when it is warm and is not holding the fast idle at all.

Temps, again agree. I'd expect with a new one to see it sit at 75-80 during normal driving, fan should come on at 90.

cdbe · Post by **cdbe** » 08 May 2010, 12:34

Thanks for all advice. My main issue with the waxstat is that the car is used for lots of short trips at the moment and it spends most of them idling at 1100 rpm - I may disconnect the cable and see how it gets on - particularly over the summer.

Not looked at sunroof yet but thanks for tips.

While underneath draining coolant from engine block I noticed that the PAS ram on the steering rack did not have a gaiter on it - I have tried various places that do the ones for the ends of the rack with no luck - I guess this will have to be obtained from the main stealer unless anyone knows otherwise? or has a good used one.

Other issues uncovered are:
rear wiper not working - should be straightforward, probably corrosion

and fuel gauge needle is erratic - moves from eg full to 7/8ths full and back again or 1/8th full to empty and back - I believe the sender is accessable from under back seat so may have a look at this first.

citronut · Post by **citronut** » 09 May 2010, 10:31

dosent the waxstat pull the cable to bring the cold start rev's down as it warms up, if so disconectting it will not acheave anything,

the power steering rem is usualy exposed and dose not have a gaitor at all,

regards malcolm

Dommo · Post by **Dommo** » 09 May 2010, 11:10

No, it's tight when cold and moves an arm/lever, which raises the idle. As it warms up the cable slackens and releases the lever which lowers the idle.

(or is that what you meant?)

But slackening the cold start waxstat cable will stop it idling high, but it may not be for the best.

citronut · Post by **citronut** » 09 May 2010, 11:47

no no Dommo i just could not think which direction it functioned, (like my brain)

regards malcolm

MikeT · Post by **MikeT** » 09 May 2010, 12:57

Dommo wrote:No, it's tight when cold and moves an arm/lever, which raises the idle. As it warms up the cable slackens and releases the lever which lowers the idle.

But slackening the cold start waxstat cable will stop it idling high, but it may not be for the best.

Hi Dommo, are you 100% sure it's not how citronut suggested with the cable pulling it tight when warm?

I'll tell you why I'm asking; on bosch pumps, the principle of the fast idle is such that a force is required to pull it closed against the idle stop, without which, fast idle is permanent.

spider · Post by **spider** » 09 May 2010, 13:42

Lucas pumps work the other way around (the cable is tight when it is cold, the stat expands the cable which lets the lever move back to its normal resting position)

Typical setting with a hot engine (say 80c) there should be about 3 to 6 mm freeplay between the end of the cable clamp and the fast idle arm.

When they wear (the waxstat) they do get a bit lazy and not always release fully.

You can do away with it as I put above, but it will attempt to idle when cold at about 600rpm and cut out on deceleration, adjusting the anti stall to compensate for the missing fast cold idle is not a good idea imo. Even in summer you want one, I spent a bit of time a couple of years ago investigating the need for them.

As a side note, some 'for hot countries' vehicles do not have them (the same ones that would not have the 'back of the block' type fuel heater fitted, just a bypass pipe. This is a bit off topic on this post though as that applies only to late 80's and early 90's ones. Not the purflux filter assembly.

Renault DCi (I think that was what it was) ones fit (although you might have to lengthen the cable) and release a lot lot quicker (as in a couple of minutes) in some ways too quick for the XUD but its adequate.

MikeT · Post by **MikeT** » 09 May 2010, 14:57

Hi Andy,

I didn't realise he has a lucas pump - got confused by Dommo's sig - he's not the OP

Dommo · Post by **Dommo** » 11 May 2010, 19:07

Oh god, sorry. I didn't realise there was a difference. I'll keep my beak out

cdbe · Post by **cdbe** » 11 May 2010, 19:58

I think I should probably leave it alone - it just offends my mechanical sympathy to have the car idling at 1100rpm for most of the short journeys it is doing at the moment. I will soon be changing jobs and doing 20 miles each way so it will then become less of an issue.