heater blows cold?

got reanulat laguna but heater only works luke warm had the enging flushed and got air out but still only gets luke warm will i need a new matrix

nik
January 2009

Had this problem and it was air in the system, just this minute fixed it.

NOTES:
-Tools: 3/4 socket set and screw driver set
-Spare fluid
-Gloves if you have sensitive skin
-Engine should NOT be running

FIX (to make it easy require two people, VERY hard solo): nice and simple, remove the cap to the header tank and leave it off throughout, make sure the header tank is full of fluid, undo the two nuts (10mnm on the car I did it on) which hold it in place and lift it up to gain maximum pressure through the system; get the other person to undo the four bleeder valves (requires screw driver though pipes can be finger loosened, rad requires screw driver) one at a time making sure to do up the previous one before the next is undone:

-Start with the outlet from the rad (top pipe)
-The the radiator its self (located top left looking at the car. Be warned the pressure is slightly higher so don’t panic as it does flow fast)
-Then the rad inlet
-Finally the out from the matrix (valve can be located just under the air pipe from the filter to the manifold)

Keep the valve undone until there is a constant flow (prepare to loose a lot of fluid) and make sure at all times the header tank is kept high and with sufficient amounts of fluid to maintain pressure.

When the system is bled, start the engine and go for a drive to get the temperature up enough to open the thermostat and that should be it :D

Sorted.

Richard Harrison
December 2007

Blocked heater matrix is a common problem because of the way they are constructed. Unfortunately water alone does not work well, as my mechanic discovered. I flushed the system with Forte BioDegreaser following the instructions carefully. Perfect result after a couple of hours work (it involves idling the engine for 30 minutes).

Graham
October 2007

The problem is with your heater pipes being blocked (I had this on my Laguna and it's a common problem if you search Google). They need to be flushed.

You need to remove the inlet pipes from the bulkhead (engine side on the right hand side, look for 2 pipes) and flush through with a hose pipe. Alternate between the 2 pipes and watch the sludge come out. Don't forget to bleed the air out on refilling.

Paul
August 2007

Find the water temperature sender. Its normally on the thermostat housing. Remove the wire then remove the sender. Now start the car and see if any air bubbles pop out of the hole. Try reving the engine when you do this.

Simon
October 2005

Phone you local library and ask if they stock vehicle workshop manuals, ours in West London did. Most heaters work on same principle even if they haven't got yours look one up and read the heater faults page.
If it's work at all before then It may be an airlock, try running the engine from cold with the header/topup tank cap off, I'm told this helps to disperse air trapped in the system.

Bob
October 2005