Hello all!!

I did a search, maybe I missed something. I have a curious problem with my car...(it was in storage for about 4 years FYI, I have been driving it since August)

The A/C has been working ok(probably need a top off of R134) this summer, so I never really checked the heater. Well its getting cold here now and my heat works great when the car is not moving but no so well once she is rolling. My levels all seem good (although I know I have some work coming up,tensioners, belts and bearing replacing etc 84k miles) however I do get that coolant smell every once and a while exiting the vehicle.

Any ideas on where to start looking?


Thank you,

Chris

First things to check:
-two one-direction valves on an octopus.
-aux.coolant pump
-heather valve
-coolant pump
Also it may be a problem with a head gasket.

The heater core may be partially plugged. Backflushing can often cure that problem.

It's very unlikely that the heater core is plugged. At idle the pressure in the cooling system is lower, so if it's plugged core it's almost impossible to get heat at idle, while there's normal heat when revving an engine.

The engine water pump does not supply water to the heater core the heater pump does that. But I did miss the point that the heater works better when the car is not moving. If it were a XJ6 I would immediately say the thermostat is stuck open, but that would be unusual in the V8. But still possible.
The heater pump or valve are more likely suspects.

This sounds very much like my experience when my auxiliary heater pump (sometimes called the scavenger pump) went out. It was intermittent at first, then eventually just died, which makes sense since it was the motor brushes that had been consumed over the course of 14 years.

If this turns out to be your issue, this pump is easy to remove and replacing the brushes is not at all difficult. I documented this in December 2012 on the JCNA forums in a thread entitled: Dead Auxiliary Heater Pump MNC6710AC? Read on. . .

Thank you everyone! I'm not sure where to start and from the suggestions it may be a bit before I figure it out. I hope to look at it tomorrow and will report back.

Chris

My money is on the Aux Pump. I picked one up from a Low Mileage vehicle at a local Pick-n-Pull for $15. $400 from dealer. Or, replace brushes, but if you don't know how that works, it can be tough.

Coolant smell should be found. The Alum Block will not like getting hot if it runs low.

Or you can remove the pump and test it on a battery and short hoses over a bucket of water....

I'm with all suggesting it's this part. Located (from the front of the car on the rhs) under the header tank, bolted onto a bracket - one suggestion would be to change the spring clips to jubilee for the hoses. Take it to bits, clean and lube it and box it back up, it's probably dry from storage.

MNC6710AC is the pump part number. Google it or put the number in Ebay. Rebuilt is better if you are going to drive car for a long time. I do sometimes get bad parts on Ebay.

flexible hose clamp pliers will make this job easier.
Bottom-line pricing on Astro Pneumatic - 9409A at ToolTopia.com

Greetings. Had same issue last winter and presenting itself again... replaced the auxiliary pump but turned out it was my heater core clogged. Was able to unclog by getting 'water hose' (light) pressure through the core (both ends). It solved the problem last winter and going down the same route again this time around (probably didn't do a good enough job last winter...). The car currently has the correct orange coolant, but not impossible that once in its lifetime it had the incorrect coolant. The clogging appears to be common with use of wrong coolant.

Cheers

Mixing the coolants is definitely what does it. I hope your radiator is okay. This is where the Realgauge would be very useful.

Refering to my radiator that might be clogged too? Good point as a matter of fact.... never really thought of that aspect. I have never had (obvious) overheating problem (even in the TX heat!) but did have a series of coolant leaks (from hoses, then thermostat cap,...) - the former done by a mechanic and while he certainly drained the coolant, not positive that any serious "flush" was done... I still have a minor leak somewhere - no clue where at this point (need to fill half a cup of coolant every.... 500 to 1000 miles?). And yes, RealGauge would be nice....

Ok, again I want to thank everyone. Pump is working. After looking through some threads I opened the coolant tank and started the engine and filled it until the thermostat opened. I got quite of few air bubbles and added maybe a quart of coolant. It seemed like there was some air in the system as it works well now. I get a cool draft by the steering column and not sure what that is yet. I know she needs a flush and just wanted to say thank you to everyone again.

Chris