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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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#35 ·
i'm having an issue with my laguna where the driver's side is working fine, i.e blowing hot when i want and cold etc, but the passenger side stays cold, even when i have it set to full hot. Any one else had this issue and managed to resolve it?

Cheers in advance for any feedback. Greatly Appreciated
 
#36 ·
I can't find a way to start a thread so I'll ask here.
Is a thermostat flange the same thing as thermostat housing?
I gave up on my thermostat change because two of three torx
bolts sheared. They go into a black plastic part. I took the part
number from the plastic part only to find it's called a flange.
Maybe the thermostat housing is in the metal part next to this.
1998 Clio RT 1.4 E7J 780 engine
 
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