All.

I’ve got a leaking heater core but have questions, not on the replacement but more of system specs and workings.

Since there is always coolant charged and circulating in the lines to the heater core how does that change when the heat is on?

I have no leak or coolant smell when temp dials are 68 or less. When 70 to 78ish I have a coolant smell but can’t see a leak. When maxed heat and fan I have the smell and occasionally see a drip from the core/line connection.

Why is that? Is it the blend door moving to change airflow or is it the core receiving some type of electrical current to activate it? It seems if it always has coolant it would always smell. But it doesn’t.

I’ve scoped it and cannot see a leak on the bottom between the core and carpet so maybe it’s on top where it connects to the rest of the system. So where would it leak from?

Thank you !

 

Part of the description from the service manual:

"The heater controls the temperature of the air supplied to the distribution ducts, as directed by the ATC module. The
heater is installed on the vehicle center-line, between the instrument panel and the engine bulkhead. The heater
consists of a casing, formed from a series of plastic molding, which contains an evaporator, heater core and control
doors. Internal passages integrated into the casing guide the air through the casing and separate it into two flows,
one for the LH outlets and one for the RH outlets.
When the A/C (air conditioning) system is operating, the evaporator cools the air entering the heater.
The heater core provides the heat source to warm the air being supplied to the distribution ducts. The heater core is
an aluminum two pass, fin and tube heat exchanger, installed across the width of the heater housing. Two aluminum
tubes attached to the heater core extend through the engine bulkhead to connect with the engine cooling system.
When the engine is running, coolant is constantly circulated through the heater matrix by the coolant pump. On
vehicles with a FFBH (fuel fired booster heater), when the FFBH is active the coolant flow is assisted by an electric
circulation pump.
For additional information, refer to: Auxiliary Heater (412-02B Auxiliary Heating, Description and Operation).
Two temperature blend doors, one LH and one RH, regulate the flow of air through the heater core to control the
temperature of the air leaving the heater. On the automatic system, the two temperature blend doors operate
independently to allow different temperatures to be set for the LH and RH outlets. On the manual system, the
temperature blend doors are coupled together and produce a common temperature for the LH and RH outlets."

Hope that helps

Jeff

 

Just a few quick thoughts, there is a rear heater core/fan assembly and the aluminum pipes in both the heater cores have O-rings for gaskets, so even a small leak might get the smell of antifreeze but would be very hard to detect without some very careful investigation. I would take a peek at the rear, which I believe is on the driver's side over the rear wheel well, but then again you may have already checked that out, perhaps someone else has some better ideas...

 

Thanks for all the responses and suggestions.

I have a leak at the heater core, for sure. Seen very small drops of coolant and had a wet carpet on the inboard side below the core.

I’d think with o-rings going bad then you’d see a much more consistent drip which I don’t. And it only seems to be really when running heat for a while in cold weather which confuses me since there is always coolant cycling thru.

Maybe a fin has gone bad or the cool and is leaking internally somewhere from the core and then drops into the ducting and one it’s full enough I see small drops at the lower pipe?

Does anyone know if the crust fittings can be undone and the new crush type smashed around existing pipes? Don’t want to change pipes.

 

I have never done this on a Land Rover but removing the heater core would definitely confirm any leaks, of course you'd have to have new O-rings and drain the cooling system first, it looks like it is a pain in the backside but not too complex. That is likely the only sure fire way to properly diagnose and fix a leak in the heater core. Perhaps someone else has actually done this and can offer some tips and suggestions...

 

Just to let you know, if you follow the service manual, it requires removal of the whole dash to include the center console and even the steering wheel.

There was a thread on here where someone just cut the lower dash near the heater core and pulled it straight out then repaired the dash. Seem like a more reasonable approach if your Rover is not a mall crawler and a small repair line won't bother you.

Jeff

 

Hi Jeff, the maintenance manual I have for removal of heater core left hand drive mentions removing the passenger side instrument panel dash support but not the whole dash, perhaps I've got the wrong manual? Red-faced in the Great White North...

EDIT:

I see that removal of the air conditioning evaporator core entails removing the whole dash, instrument panel, steering wheel assembly and centre console, definitely a monster of a job, the heater core is not easy, but not on the same scale as the aircon stuff. Having never done the heater core on my machine though, I'd want to research it very carefully before attempting it, a more thorough read of the passenger side instrument panel dash support instruction reveals that the centre support and the glove box also have to be removed, which might have some nasty surprises in store for the would be Land Rover mechanic...

 

I was thinking evap core. not heater core. still, IF I had it to do again in the my Rover which we use for overlanding and camping (vs my wifes mall crawler) I would just cut the dash in a way that it could be repaired and not be too obvious.

Sorry for the confusion.

Jeff

 

That's quite alright, working on the heating/air conditioning is a big job, found some more information on this thread https://landroverforums.com/forum/lr...er-core-77193/ ...