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Cold Heater (again)..........

59K views 36 replies 22 participants last post by  jhribar1 
#1 · (Edited by Moderator)
Cold Heater Fixes (Laguna & others? - Repeat)..........

Hi All,

Just a short-ish :rofl: thread to note that the usual flurry of heater problems are surfacing as the cold weather descends on us.

For those that haven't found it, (retreated way down the archives now), I put together a long 'how to' article some time back.

As its not the first item that pops up on a search, here is the URL to the original 'How To' Article:-


http://www.renaultforums.co.uk/showthread.php?t=5107


A few additional points:-


1) Heater matrix flow:

If, as per the article, you've flushed out the heater core (probably more than once is necessary on a really gungy system), the flow through the heater in/out pipes at the bulkhead should be significant if using a garden hose.

A low or slow flow probably means there's still a partial blockage.

2) Thermostat:

As already pointed out by others, can fail open OR shut.

Shut will obviously give over-heating problems, while Open will (likely) give over-cooling issues.......and a chilly heater.

From our own car and comments from others, it seems that the Temp Gauge should run at the halfway point as a 'norm' - is yours higher or lower - is that a clue?.

'Stats can be obtained in different temp ranges of which the more usual is in the 86/88'C band. Other types may have been fitted in the past in an attempt to 'cure' a problem (?). Opening Temp is usually stamped on the stat's flange - maybe yours is high (or low) ?


3) RAD-Sealer 'gunk'......

While this stuff obviously works quite a lot of the time (yes we've all used it at some time or the other!), the number of cooling system problems I've encountered on cars a few weeks after administering it is 'legion'.

The problem occurs when you have a leaky system that's getting air into it (which will of course happen if the water is disappearing).......the heat and the air 'set-off' the sealer and this can be in the tops of the rad core and of course the heater........with all the attendant problems that can cause.

(IMHO) ;)

4) Diagnosis:

Try and use a bit of 'logic' when it comes to finding the cause, (as some here are already trying), i.e. which bits get hot? which bits stay cold?, which bits are cold but should be hot?

Where possible, unhook the pipes and examine carefully....apart from the usual gunge furring up a pipe, I've seen the inner walls of rubber hoses collapsed inwards on many occasions - which has serious flow effects.

Heat rises, so the top of the rad / engine will usually be that bit warmer than the bottom.

5) Water Pump:

When was this last checked /changed?

I'm no long-term expert on the Laguna / Renault pumps, but have had many cooling problems over the years caused by corroded /erroded water pump vanes. This often manifests as the engine being a little prone to getting hot but bigger problems at the periphery (e.g. heater core) where the flow/ pressure from the pump degrades to a point where the pipe-work at the 'edges' doesn't get sufficient water.

6) Air-Locks:

The all-important, 'have you done anything to it recently?' question that might lead you to suspect that you got air into the system somewhere, somehow.

Open the various air-bleed valves - cautiously (hot water!). You should get water out -if not then question why. (Note that sometimes a bit of crud can block the small bleed-hole(s) so clear it with a thin something or the other).

Anyway, hope this and the 'old' article helps someone.

Regards,

Spiro'
 
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#13 ·
My first posting!

When driving in the snow the other day (-1 degC) I noticed pretty quick that the temprature gauge started to drop and I had to turn up the heater to keep warm (1.9DCi 2001 Megane). I know diesels are cool running but I wanted to see whether others experienced the same.

Great forums going to clean my EGR soon!
 
#18 ·
heater not working

:confused:hi im new to this but ill explain as best as i can ive just got hold of the espace 2 i think
it is k reg 1994 with 2lt inj engine ....the problem is that im not getting any heat in the car ive found two bleed nipples on on the top hose and the other one on the matrix pipes under the bonnet .....i dont know if thers any others i cant see anymore ?, ive toppped the expansion tank up and run the engine squeezed the pipes to force water up into the heater.....and still no heat.....the engine seems to be running at normal temp but its not getting through to the interior heater ,i read earlier that theres a cable to a water valve that controls the flow to the interior heater does anyone know the position and how to check it....any help much appreciated...
 
#19 ·
heater probs

hi again just wondered if id got the wrong section for heaters on the espace,is this a common fault,i got the car off of my dad and he said it hadnt worked since hed had it,lol, the probs still the same no heat the engine dosnt overheat,no air in the system,ie blown head.i dont know about the thermostat ?if i take that out would it solve the problem?
 
#23 ·
Hi all,

I have a heater issue, erm lets start with what i know.

Changed thermostat, checked the flow through my matrix not brilliant, but i have toped up with water then blew the water through and there is a flow there, but lots off brown sludge came out. Rad pipes one is hot the other luke warm, and when vented from the rad there is no air coming out and there is good pressure as in the water flows out well, again very rusty colour.

My fan works in all positions, and the heater controll cable seems to be working in the cold position, then trhough to the hot i only get a small amount of heat, any thoughts.

I will try with the heater again tomorrow with a hose this time and i will back flush, but does anyone else have any tips ?

Regards
 
#24 ·
I will try with the heater again tomorrow with a hose this time and i will back flush, but does anyone else have any tips ?

Regards

Hello eddie31 :) The cooling system is very often neglected TBH I'd back flush the whole system out, & make sure when you bleed the system

1 Make sure that you know where ALL the bleed nips are.

2 During bleeding release the cap on the expansion bottle so that air can replace the water that goes into the cooling system.

3 Run the engine on completion until the fan cuts in a couple of times.
 
#25 ·
Cheers for the quick post Hondo !

Ill try all this tomorrow i have aquired a hose pipe now, so i will flush the rad and engine block as one, then i will turn my attention to the heater, i tried some soda crystals today, sort of worked, but i think because i never back flushed it just all got clogged up again when i ran it.

Do you knoe how to actually take the matrix out ? i have the haney manual but its a bit sketchey when it comes to this, i have took out the facia with the temp controller on it, and checked the cables were ok.

As i say i only picked her up about 2 weeks ago she is on a N plate and has only done 56500 miles, cost me £120 to put her through the MOT but she still needs the back brake cylinders replaced they are leaking slightly, and the heater issue.

I have done an oil change, renewed all filters and spark plugs, plus i fitted a new thermstat. I think once i get this heater sorted i will put new coolant in on a yearly basis, i dont think people realise how much damage can be done from leaving it in.

Again cheers, ill let you know tomorrow how i get on

Regards
 
#32 ·
Hi, it seems heaters are the Achilles heel of Renaults, having had problems with an old Laguna that ended up being a "dry joint" on the thingumyjig behind the glove box, I now have a 2007 Scenic with a duff heater.

The fan works fine on all settings, the aircon works fine & it will put out heat on the window demister too, but by feet are freezing !

On the old car there was a cable operated flap that channelled air either from outside or from the heater element, I presume the problem is to do with this flap.....only now I bet its electrically controlled :mad:

Can anyone tell me where abouts this is & has anyone had problems with this & what did it turn out to be ?
 
#33 ·
Freezing Feet.

I've had more Renaults than I'd care to count & cold feet has been a common denominator, the last one I had (A Megane) which was purchased new, I was convinced this would be an end to the problem. But no, it wasn't :devil:

If you do what I ended up doing, get your head right under the dash & look at the heater outlet on both the drivers side & more importantly the UK passenger side you're going to find the air outlets to the UK passenger side is very approx 50% more than it is to the UK drivers side :devil: Which explains why my OH was always saying her feet were too hot, while mine were bl00dy freezing. :(
 
#34 ·
In my Scenic its cold on both sides, at both feet & dash vents, I blocked the rear vents with kitchen roll to boost heat in the front & still nothing :(

I broke my ankle a few years ago & it hurts like hell when it has cold air blown on it.

Whilst I'm moaning, I also find the buttons for the heater / air-con dangerously fiddly to use when driving, not like the nice chunky buttons in my old mk1 laguna, I tried to get the missus to operate it but she can't get the hang of the ruddy buttons & so it makes it even more dangerous as we fight over the blasted thing :devil:
 
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