E30 325i Heater matrix bypass

[Qasimahmed]

Hello all

Since I first got my E30 I noticed the heater pipes have been bypassed and a loop has been created for the heater pipes. I understand they had issues with the temp valve and the matrix leaking. What's the best way of diagnosing which is the problem. I'm thinking of reconnecting the lines and checking the temp valve for leaks. Can you see the heater matrix leaking without removing it?

Thanks
Qasim

[Brianmoooore]

A small leak in a heater matrix will show itself up when you go to demist the screen. A leaking one will make the problem worse before it improves.
50 leaking valves for every leaking matrix, and a valve that has been leaking is usually fairly obvious, with stains running down the side of it. There are also a couple of O rings in the joints. Could be that simple.

[Qasimahmed]

Thanks for that Brian. It seems your 100% right. Is it just a 12v positive and negative to activate the valve. Just so I can see if it's working when it's out.

[BenHar]

Don't worry about whether the valve actuates or not. It only turns the water flow off when the control is set to minimum.

The main thing that affects the temperature from the outlets is the flap valves which control the air flow.

If you fit o-rings in the valve in place of the diaphragm the water flow will not be shut off but it won't be a problem.

Ben

[Bonymaenjack]

If I may , my heater matrix blew just before Xmas and to be honest for the cost of a replacement , if i was messing around with the valve, I'd change that as well

[Qasimahmed]

Right ok, I'll fit the o ring and reinstall.

If I'm honest I didn't even look at how much a matrix costs but I guess if I'm there, I might as well replace it if it's not too expensive.

Thanks a lot

[Bonymaenjack]

Right ok, I'll fit the o ring and reinstall.

If I'm honest I didn't even look at how much a matrix costs but I guess if I'm there, I might as well replace it if it's not too expensive.

Thanks a lot

They do vary in price, I bought mine from Amazon and it was £28, a Nissens 70501 , The one I replaced was OEM and the main body of which is plastic split open discharging its contents everywhere inside the dashboard. ( I'm still putting everything back to together, the car's park up for the winter atm) )

[Brianmoooore]

As ever, with failure of the valve or matrix, check that your coolant bottle pressure cap has been replaced by the modified type.

[Qasimahmed]

That was one of the first things I did check, it does have the new cap installed. I can't remember what pressure rating was on the cap but I do remember it being the correct one.

[Brianmoooore]

It's the 1.4 bar ones that were recalled. 14 on the cap.

[MunsterScot]

Not wanting to hijack the thread but what pressure rating should the cap be? I've got the one with 14 on it so will look at changing it as I've also got the heater matrix bypassed just now as it leaks.

In the E30 WIKI it says "For that reason, BMW introduced a new pressure cap, rated at 1.4 bar. If there's a chance that your car is still running its original tank cap, take your VIN to BMW and claim your new, free tank cap."

[Brianmoooore]

The rating of the cap depends on the age and model of your E30. Early stuff used a lower pressure, and the iS uses a higher pressure, but the vast majority of E30s use a 1.4 bar cap. Most, but not all, of the uprated caps have a yellow disc on their underside.

[martauto]

does this apply to the M10 engines Brian ?

Mart.

[Brianmoooore]

does this apply to the M10 engines Brian ?

Mart.

No, M10 cooling system operates at a lower pressure. It's a very old design (1930s?), updated by the strange thermostat hanging on the hoses.

[Qasimahmed]

Anyone have any ideas as to removing the 2 bolts on the back of the heater matrix outlet. It's quite close to the bulkhead with limited space.

Thanks

[Brianmoooore]

From the engine bay with a 1/4" socket on an extension. Push the extension through the grommet from the engine side, then fit the socket.
For the cross head screw where the brake quadrant bracket gets in the way, use a cross head bit of the type that fits in a drill holder, and turn it with a 6mm (preferably ratchet) spanner

[Qasimahmed]

Thanks a lot Brian that's how I finally got it out, needed someone to help from the engine side of things but all sorted now.

[Bonymaenjack]

Thanks a lot Brian that's how I finally got it out, needed someone to help from the engine side of things but all sorted now.

Too late now , but I cut down a 6mm spanner which worked ok ,My problem is realigning the brake clevis arm to reconnect the brake linkage to the rear of the servo

[Brianmoooore]

Turn the rod until they line up, drop the pin in, then adjust.

[Bonymaenjack]

Turn the rod until they line up, drop the pin in, then adjust.

This is the second time I've replaced a matrix , and the first time|I had no bother with refitting the linkage ,this time I've adjusted the clevis at the servo end but now the pedal is higher than the other two, Will the rod itself turn within the clevis to bring the pedal back down ?

[Brianmoooore]

The rod has a LH tread at one end and a RH thread at the other. It's the only bit you should be adjusting.
There's a locknut on it to slacken first, and two small flats on it near the clutch pedal, for a small OE spanner.

[Bonymaenjack]

The rod has a LH tread at one end and a RH thread at the other. It's the only bit you should be adjusting.
There's a locknut on it to slacken first, and two small flats on it near the clutch pedal, for a small OE spanner.

Cheers Brian
To to do it properly do I slacken both ends or will one suffice ?

[Brianmoooore]

There's only one locknut.

[Bonymaenjack]

One lock nut but a clevis at both ends ? l'll have a look next time I'm in the sons garage. I know I didn't have any problem the 1st time so its must be me .

Cheers

[Qasimahmed]

Just for anyone who is going to remove the heater matrix. I removed the bracket for the abs pivot spring and then removed the clevis on the brake booster side. After that the matrix came out quite easily. New one went in just as well.