Heater's not that hot even on full

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Post Reply
stu9
Posts: 257
Joined: 23 Oct 2012, 18:56
Location:
My Cars:

Heater's not that hot even on full

Post by stu9 »

03 C5 hdi

Just had fresh coolant the other day, but even before he did it, it's like this, basically the heater's got to be on full to get decent'sh warm (not hot) air, if you turn it to half it's cold....the mechanic said it could be a blocked matrix....anyone got/had this
411514
(Donor 2017)
Posts: 421
Joined: 14 Dec 2010, 15:26
Location: Sheffield, Uk
My Cars: Citroen C5 2.0 Hdi 2003
x 39

Re: Heater's not that hot even on full

Post by 411514 »

Hi, when you changed the coolant did you change the thermostat or is the current one known to be good.
I have the same car and find that the temp control isnt particularly sensitive between no heat and full heat, although at full i do get really hot air.
I assume you have a water temp gauge as mine does in which case is this showing hot. In current climate mine takes around 25 mins town driving to reach full temp, if yours is not reaching full temp in this time then its likely you have a bad thermostat opening too soon.
If your water temp is indeed reaching 75 ish celcius and your still not getting hot air i wouldnt particularly suspect a 'blocked' matrix unless you have other reasons for thinking this, id first suspect a poor heater flap adjustment. I belive on the c5 it is a motor driven flap rather than a simple cable between knob and flap (oo'errr), so maybe check this out first, sam

Edit: make doubly sure there is no air in system after coolant change
Sam

2003 C5 2.0HDI 110
stu9
Posts: 257
Joined: 23 Oct 2012, 18:56
Location:
My Cars:

Re: Heater's not that hot even on full

Post by stu9 »

No it wasnt touched, and the only reason the coolant was changed was because the mechanic drilled/tapped the hole in the head for the injector, thing is, the blower's fine, just the heat. I'm not saying it's cold when on full, it's warm not hot....maybe I've been to used to the one in the Pug...it's great!.

The engine temp heats up quick as in about 5 mins and it's more/less half way....just the heater, I'll check the flap carry on, but if ok, I'm stumpted, well apart from putting a new stat in
citronut
Posts: 10937
Joined: 29 Apr 2005, 00:46
Location: United Kingdom east sussex
My Cars:
x 92

Re: Heater's not that hot even on full

Post by citronut »

going by what others on here say regarding HDI's heating up taking a long time is normal, so if thats true yours should not get to full temperature in 5 mins,

could the pollen filter be blocked, although i think if this were the case you would get reduced blow/air through vents,

feel the two heater hose's down the back of the engine,

did the mechanic bleed the system fully ????

were are you located
Regards, malcolm.

current ride a BX 1.7 TZD estate
1986 MK1 BX 1.9na D Auto(in Mothman Andy's stable )
layed up roppy 1.9TD XANT estate, now gone to meet her maker
purple and lilac metalic 2CV(VIOLET)registered to her in doors
1972 DS special been layed up aprox 31 years
stu9
Posts: 257
Joined: 23 Oct 2012, 18:56
Location:
My Cars:

Re: Heater's not that hot even on full

Post by stu9 »

I know, I too think it heats up to quick for a diesel, my 306 hdi takes alot longer, dont know about the pollen filter, but there's plenty of air through the blower. I check the heater hpipes tomorrow, both should warm/hot I take it.

I hope he did, he pulled the bottom off, then once finished what he doing, filled it up, and I take it with the heater on full as to let it into the matrix....I had to go out though before he finished, so I hope this is what he did.
citronut
Posts: 10937
Joined: 29 Apr 2005, 00:46
Location: United Kingdom east sussex
My Cars:
x 92

Re: Heater's not that hot even on full

Post by citronut »

its not necessary to have the heater on hot to bleed the coolant system as they dont have a valve/tap on modern cars any more,

the system just diverts the heat using flaps in the heater box, so coolant is flowing through the matrix all the time,

and yes both heater hose's/pipes should get equally hot,

also these should heat up without the thermostat being open, as they are both the engine side of the stat so you get heat in the cab before the engine reach's full working temperature
Regards, malcolm.

current ride a BX 1.7 TZD estate
1986 MK1 BX 1.9na D Auto(in Mothman Andy's stable )
layed up roppy 1.9TD XANT estate, now gone to meet her maker
purple and lilac metalic 2CV(VIOLET)registered to her in doors
1972 DS special been layed up aprox 31 years
citronut
Posts: 10937
Joined: 29 Apr 2005, 00:46
Location: United Kingdom east sussex
My Cars:
x 92

Re: Heater's not that hot even on full

Post by citronut »

ps.
try running the engine with the cap off and watch the coolant level, of/as it drops top up as required, once it stops asking for more coolant replace the cap and wait for the fans to kick in then back out, now carefully open the cap to check if its all calm and the level is still correct,
then re/check the level once the system is stone cold,

if this is all ok it could be a temp sensor somewere in the system, in which case you will have to wait till Steve ( Myglaren ) or other highly tech'y types kicks in,
as i know nout regarding that side of things on a C5 give me a dersh ( 2CV ) then were talking
Regards, malcolm.

current ride a BX 1.7 TZD estate
1986 MK1 BX 1.9na D Auto(in Mothman Andy's stable )
layed up roppy 1.9TD XANT estate, now gone to meet her maker
purple and lilac metalic 2CV(VIOLET)registered to her in doors
1972 DS special been layed up aprox 31 years
User avatar
myglaren
Forum Admin Team
Posts: 25366
Joined: 02 Mar 2008, 13:30
Location: Washington
My Cars: Mazda 6
Ooops.
Previously:
2009 Honda Civic :(
C5, C5, Xantia, BX, GS, Visa.
R4, R11TXE, R14, R30TX
x 4888

Re: Heater's not that hot even on full

Post by myglaren »

citronut wrote: if this is all ok it could be a temp sensor somewere in the system, in which case you will have to wait till Steve ( Myglaren ) or other highly tech'y types kicks in,
as i know nout regarding that side of things on a C5 give me a dersh ( 2CV ) then were talking
You have far too much faith in me Malcolm - I would have piped up earlier if I had any different opinions that those already submitted.
I have not had the pleasure of this experience yet but agree with the above that the system may not have been properly bled, which seems to be a problem for some owners - again, I have never had a problem bleeding mine whenever the system had been worked on.

From comments that others have made, I do wonder if the matrix may have become clogged with K-Seal or similar? It does seem to cause some unwelcome side effects.

After eliminating the possibility of air in the system, then the thermostat as a precaution - I have known one start to break up and cause some similar problems although overheating is the more likely result there, it may be advisable to drain the system fully and flush it, then flush with Forte Cooling System Flush, check the operation and if satisfactory refill with Citroen Coolant and Forte Cooling System Sealant.

The Forte products will do no harm even if they do no good and Valeo insist on the use of the sealant when a new matrix is fitted or the warranty is invalid.

I have just had a new timing belt, water pump and tensioners fitted, the cooling system flushed as described above and the relevant Forte products used.
Belt and braces - there was nothing wrong with any of it but I'm confident that it will last a while now.

I did have a problem with this car when it was really cold, when I first bought it, in that it would occasionally on start up, when stone cold after being left overnight, show max on the water temperature gauge, and flag a warning that the coolant was too hot. I ignored it as I knew full well that there was no problem with it and it would reset after about half a mile.
Performance at the time was abysmal and replacing the sensor, cleaning the MAF and pipes made a very dramatic improvement.
Post Reply