Mondial t heater

My heater works for jack. It works, but gets lukewarm at best. OK, so prime suspect would have to be the auxiliary pump. I wondered where it is - looked at the parts book so helpfully published online by the esteemed folks at Ricambi America - that made it look like it was somewhere in the engine compartment. Well, last night, after the most enjoyable drive I have yet had in the car, I took a light to the engine compartment. Sure enough there it was, tucked in the fender behind the overflow tank. And guess what? There was liquid underneath it. So the little sucker is leaking which probably means its seal is bad which probably means that the motor is not spinning at all. Hmmm. Light at the end of the tunnel, what?

Now, I appreciate the good folks at Ricambi, but I can't always afford their offerings. In the case of the pump, they sell a very nicely put together kit with all the fittings - literally everything you need - for $437. Can't afford it. So I got out my Google cap and went to work. Turns out what looks like a 97% identical pump is used by VWs and Audis. AutohausAz has it for $95 and change w/ free ground shipping. Then I think you need an electrical connector as the Ricambi kit comes with one - the og pump has a different wiring set up methinks. Anyway ordered a mini 2 wire female amp connector w/ angled rubber boot from my friends at EagleDay for $19 and change incl. shipping. (BTW, the place to get Tenax Fasteners, except for the Black Cavallino ones, which Ricambi has.) So, I am in $115.

Will report on the installation, which will also include the replacement of my thermostat and either helicoiling or rethreading the bleeder plug opening on the thermostat housing, while a partially drained condition obtains. More will be revealed, as the man said.

One note: there is a discontinued auxiliary pump used by certain Ford models and made by the extremely competent folks at Airtex. Supposedly a few places still have them. Very tempting, as I am sure that the Airtex pump will last forever, as opposed to the Bosch pump which didn't even last 20 years. For now I am going to go with the cheaper Bosch pump ($95 vs. $165), but once I have the old one in hand so that measurements may be taken, I may well end up replacing it w/ the Airtex if it looks like it will fit.

 

First I would look at the pump. Yours may well not be completely kaput like mine, merely on its way out, so working intermittently. Take it out, connect it to a water bucket and 12 volts. The intake is the center barb. Attach a piece of hose to it and dangle it in a bucket, aim the outlet at the bucket and fire it up. Any inconsistency or noise, I would replace that sucker. Mine is leaking and yours is likely to be nearly as old as mine.

Other suspects:
The suction fan. In the dashboard (next to the left hand tweeter) there is an opening that leads to a temperature sensor that is part of the climate control's thermostat. Behind the sensor is a tiny squirrel cage fan that serves to circulate cabin air across the sensor. If that fan is not working, or the passage or sensor are dust clogged, then the sensor will report inaccurately. You can see the squirrel cage by looking up there from underneath the dash, although I have to take my seat out to get under there. 3 minute operation that, so no biggy.

Other poss. is the valve that controls flow of water to the heater core. That is down by the passenger footwell, just above the footwell proper on the right side. That one would be a bit of hassle to test, but not impossible. Check the pump first.

 

(With apologies to Lynard Skynard)

Oh boy, that is a toughie. I still would check the pump, although when mine leaked, I didn't smell a thing. Bummer. Go for a good drive and get everything all warmed up. Then stop and see if you can tell where the smell is coming from. The engine compartment - it's the pump. The passenger foot well - towards the outside - it's the valve. The center of the car under the dash, YIPE! - its the heater box. That would be efyucekayeede! I am sure that you could find a used heater core, but replacing it would be an adventure and a half. If you are very lucky, it would turn out to be one of the hoses going to and from the heater box.

 

Hi Rik,

Don't know what you are talking about. The "radio button" style A/C panel on my car is non-functional, so I have two vacuum lines that I plug and unplug as needed. Actually, I only mess with the one line as the other is for re-circulation, and I don't like breathing re-circed air. I also added a temporary switch to turn the fan on and off. Close? What is the "fix"?

 

I would have never known that about the cavallino caps! Thanks!

Still don't have my new pump, so nothing to report yet.

Hey Rik! What is "the fix"????? Can you point us to a thread? I don't think that I am the only one who is curious.

 

Weeeell, I installed my replacement pump. It fit, but the job is not for the faint of heart. The new pumps "barbs" are meant for larger diameter hose, but my hoses were stretched at the ends. Why, I don't know, but it meant that I could just get them over the new pump's barbs and secure them with the hose clamps. I don't think they will leak, but it sure would have been nice to get the hoses on all the way. Anyway, the pump is a lot higher quality unit than the oem one. It has what appears to be magnetic drive, so leaking should not happen again. On the other hand, I now doubt that the pump was the problem. Reason being that in order to figure out the polarity for the new pump, I had to bench test the old one. The old one has a black wire and a brown wire. The black wire is connected to the harnesses' green wire and the brown wire is connected to the harnesses' brown/? wire. So, when I put positive 12 volts to the old motor's black wire it spun in the correct direction. What a relief, because if it didn't spin, there was no way to figure out what the polarity is supposed to be. The diagram just shows two wires going to the control unit, so that was no help, but the bench test revealed the correct answer. However, the fact that it spun means that it probably isn't the bad guy. Oh well, leaky is bad enough to deserve replacement, and it's nice to get the job done for $100 instead of $400.

Can anybody tell me where the control unit is located?

Next, I'll guess that I'll have to investigate the valve.

What is "the fix"

 

Thanks Marco, I'll try all that stuff. My A/C doesn't work at all, but how that would affect the heater circuitry is anyone's guess.

I re-did the hoses going to the new pump. All it took was a couple short pieces of Gates 3/4" heater hose, two 3/4" to 5/8" barbed adapters and four hose clamps. Plus a lot of guts when it came to re-doing the hose that goes up to the heater core. That one is buried in the rear fender, but if you push it in and back you can just barely manage to feed it back out again only in front of the rear shock. Then you have enough of it exposed to cut off a piece and splice on a (bit longer!) piece of 3/4" that works perfectly with the new Bosch pump.

I was able to confirm the polarity as it finally penetrated my thick skull that if I wanted to see voltage at the pump, I had first better turn the heat control knob towards the heaty end of its travel. D'ooooh! Anyway for the record, the green wire coming from the mysterious "control unit" is the positive.