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No heat at highway speeds //M6

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Chris Wright

Post by Chris Wright » Mon Jan 05, 2015 11:04 pm

Da_Hose wrote:MTC is the brand name, Sansouci. The Bosch cores are scarce and the MTC is the one everyone ends up getting if you order right now.

I'll take pics as I go Chris, but look at the pic. I posted previously. Notice how the Bosch (left side) has no metal washer under the e-clip. Also, the plastic nose piece under the e-clip fits tightly to the center pin, but on the Bosch units there is a little bit of slop.

From what I see, the fix should only involve removing that metal washer and using the right size drill (I have a machinists set with lots of incremental sizes) to open up that nose piece.

Jose
Ahh ... I think I see now ... thanks! I need to dig around and see if I have an old one and disassemble it to see how the plug at the end connects to the stopper inside.

Chris Wright

Post by Chris Wright » Mon Jan 05, 2015 11:07 pm

sansouci wrote:I guess I'm dense: what is an MTC?
A Manufacturer of substandard parts, much like "Uro".

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Da_Hose
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Posts: 3140
Joined: Fri Mar 07, 2008 8:15 am
Location: Napa, Ca.

Post by Da_Hose » Tue Jan 06, 2015 6:40 pm

It would be great if you could break down a Bosch part, take good pics. and maybe even get some measurements.

Jose
1987 M6 - My dream car

Chris Wright

Post by Chris Wright » Fri Jan 09, 2015 11:56 pm

Da_Hose wrote:It would be great if you could break down a Bosch part, take good pics. and maybe even get some measurements.

Jose
I had a quick look and couldn't find the old one right away. I'll have a better look this weekend.

six shooter

Blistering cold here....

Post by six shooter » Sat Jan 10, 2015 4:47 am

Gotta shout-out to Barry for fixing me up with a damn nice used
heater valve. Installed it about a month ago.

Very nice and toasty warm in the Bavarian Ferarri. It was very cold other
morning and I had it at Max temperature. Whoa, that nearly melted my
rubber soles..
After doing a autopsy on the 1987 valve, the solenoid was weak and could not
hold the valve in place.
I have the plastic unit if someone has a cracked housing.
Free plus shipping.

Gotta help a brother stay warm

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Da_Hose
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Joined: Fri Mar 07, 2008 8:15 am
Location: Napa, Ca.

Post by Da_Hose » Sat Jan 10, 2015 6:22 am

I'll take that housing. I tried fixing the MTC valve I have and no dice. It still closes off over 2500 rpm.

I will move forward with a direct acting valve conversion and using an OEM housing could let me keep the check valve and use the stock mounting points easily.

I'll PM you.

Jose
1987 M6 - My dream car

JoelR
Posts: 49
Joined: Sun Mar 09, 2014 4:19 am
Location: DFW (Plano) Texas

Post by JoelR » Thu Jan 15, 2015 2:35 am

Big thanks to all who have contributed to this topic. My Bosch valve had a tear in the diaphragm, so I bought the MTC valve. It exhibited the same symptoms (no heat above 2k rpm), so I was glad to read about swapping the plastic spacer from the Bosch to the MTC. It works like a champ now!

The Bosch spacer itself has a larger inner diameter (as previously stated), but it also has three ridges that keep it centered on the shaft, as opposed to a perfectly smooth bore.

(Also, in case you are contemplating doing this and did not already know, the heater valve is located in such a way that you do not have to drain the coolant to remove it. Two small bolts and 4 small screws is all you have to remove. However, it is a bit tricky to get the E-ring back on after swapping the spacers - just be patient.)

Joel
1983 633CSi 5-speed Black & Tan
2008 X5 4.8i
2004 MINI Cooper S 6-speed
2001 Z3 3.0i 5-speed
DFW Texas

GazM3
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Location: Melbourne, Australia

Post by GazM3 » Thu Aug 20, 2015 3:46 am

I'm revisting this thead.
Mine is doing same (closing at 2000rpm). Has anyone replaced the valve with a N.O. 12v solenoid valve?

It's really annoying having the heat stop when cruising in cold weather.
Also what is the pipe size as it's a bit of a pain to measure the valve as I have the plenum in the way.
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