KV6 heater slow to heat up

[Bullnose75]

So,now the cold weather has finally arrived am having probs with the heater in the Tourer from cold starts/clearing screen of ice.mist etc.
The KV6 in it takes ages to get the heater up to temp for some reason ?
All functions of the heating/cooling on the Tourer work perfectly apart from it taking ages for heater to get hot.
Can prob rule out water pump (new) or airlocks since it's the same before and after Lates recently did the cambelts and refilled coolant with his vacuum gizmo connected.
Take today for instance -2c this morning,frost on screen. Fired up the V6,set temps to high,all air going to front screen. Sat there for ten minutes,no hot air from screen vents,just very slightly warm. Drove down village and back,round trip of 6 miles or so,still only lukewarm air from screen vents.
Back home I removed drivers side footwell panel covering heater matrix and then drove into Clacton 8 miles away. After brief stop at tip carried on to Clacton and when I got there the heater was at last flowing fairly hot air but it wasn't until the return trip that heater actually flowed hot air.
Got back home and heater matrix pipes were both too hot to touch so heater matrix prob not blocked.
Have checked the sensor grill for the ATC next to steering column wasn't clogged up with fluff,all clear.
Even at motorway speeds heater takes ten miles or so from a cold start to flow hot air.
My old Focus heater would clear the front screen of ice in a few minutes.
Am wondering if it's the thermostat not working right,maybe it's stuck open ?
In hindsight,maybe I should have had Lates replace that too while he had car in bits.
I know the diesel 75's have probs with cold running and have heard they put another inline thermostat into the top radiator hose to get their heaters working.
Is that something that might work on the KV6 too as that's easier to fit than replacing the factory one ?

Still like the Tourer but it does test my patience at times,lol
Threading a reversing camera cable through the tailgate rubber grommet yesterday was a right faff.
Just need heater to warm up quicker like a normal car does !
Paul

[vitesse]

Doesn't sound like my KV6s at all. All nice and toasty even in our climate (currently minus 11c). Although when I bought one it was only just getting to 80c but after a thermostat change is now much better.

Suggest you run T-Cut's diagnostic test then you'll be able to see if you're getting up to temperature or not. Mine runs at 94c, if much difference it's probably time to change the thermostat.

Link: https://www.the75andztclub.co.uk/for...ad.php?t=55585

Regards

[T-Cut]

I'd suggest the matrix is pretty silted up. The in/out hoses will both eventually get very hot, but that doesn't mean the matrix is delivering enough heat. It's the flow rate that's too low to operate the heater. I'd suggest you disconnect the hoses at the firewall and back flush the matrix with a hosepipe. That might clear out enough debris to get it working. If not a full descale is needed. Or replace it.


TC

[Brunty]

Something is obviously wrong. My V6 heats up a lot quicker than my 1.8. Within 5 minutes everything is up to temperature. Check thermostat is working correctly.

[Bullnose75]

Ok guys,just ran the diagnostic mode number 7. Fired up engine - reading 45. After 15 minutes at idle reading 85 (still cold heater vents)
After 20 minutes at idle reading 91 (increased rpm to 2500rpm reading dropped to 87 but returned to 91 when back to idling)
After 30 minutes at idle reading 100 (heater vents still quite cool though)
Looking like heater matrix could be blocked like T Cut suggests hey ?

[vitesse]

Sounds like T-cut has the solution. I find the diagnostic temperature very useful whenever temperature related problems arise as we all know you can’t rely on the analogue gauge. Now you have the numbers I think we can rule out a stuck thermostat.

I used compressed air when emptying my coolant system and found the short bursts of air agitated the debris in the coolant, could imagine it would work well doing the matrix, then flush until it looks like you could drink it. Try and catch the expelled coolant as that’ll give you some idea of what, if any, debris is being expelled.

Regards

[Bullnose75]

Popped out in my Rover 75 Tourer Igloo car again earlier today after scraping ice off both outside and inside of front screen,which I had to do again before my return trip from my mates place ! Oh what fun,lol.

Had a quick look at removing heater matrix to flush it the other day but the phillips screws holding the pipes together where the o rings are were done up silly tight and started to burr over without coming undone. Grrrr !
Will get them undone at some point though and remove heater matrix for a flush but before I do was wondering if there is an electric or vacuum operated valve inline in the heater pipework somewhere that only opens to let water flow through heater matrix when heat is called for ? Like on some other cars ?​
Just curious as after running car for an hour or so the heater works perfectly,getting too hot on max setting. My thinking being if heater matrix was blocked and/or silted up it maybe wouldn't get really hot eventually like it does and maybe if there is a valve that controls when/how much coolant flows through heater matrix if that said valve is slow to open that might be the cause of my slow heater warm up ? Just a thought.
Can't hurt to flush heater matrix though

[SD1too]

Originally Posted by Bullnose75

... was wondering if there is an electric or vacuum operated valve inline in the heater pipework somewhere ...

No there isn't Paul (although my SD1 does have such an arrangement).

Regarding flushing the heater matrix, I've never had to do this myself but it would appear to be easier to access the flow and return hoses under the bonnet than struggling in the footwell. Just a thought.

And a tip for you:

Originally Posted by Bullnose75

After 30 minutes at idle reading 100 ....

This is the slowest possible way to coax an engine to reach normal operating temperature and also results in maximum engine wear. Try starting the engine from cold and driving off straight away. You'll find that the temperature increases much more rapidly (as recommended in the owner's handbook). My V6 reaches 75 degrees C within a mile when doing this.

Please let us know how you get on with the flushing.

Simon

[COLVERT]

Very strange. A blocked matrix is just that. It doesn't un-block itself with time.
Even if very cold outside you should be able to get lots of heat after about ten minutes driving. Maybe your problem lies elsewhere.---

[Bullnose75]

Yep,is strange aint it ! I have the footwell panel that covers access to the heater matrix off at mo so I can check pipes for heat and the pipes in and out of it don't get hot for ages then after about an hour driving they both get hot,as does the heater,and then heater performs normally. But next time you start car after it's sat overnight same thing happens,no heat from heater for around an hour then it works fine !
Maybe my Rover has a Poltergeist in it,lol.
Joking aside,if I could feel the pipes getting hot after ten minutes of running but had no heat from vents i'd maybe think it was a heater flap door problem,ie,them not allowing air to flow through the heater matrix but the pipes don't get hot for ages and only when they do does the heater work properly.
Didn't get around to removing heater matrix today after all but hope to remove it and flush it out or flush it out through the pipes under bonnet later this week