Heater / Water pump test

[NigeElan]

Hi All, I’ve been scouring through LEC to get answers to my current problem with my Elan, but I keep reaching dead ends.

So, like others, I’ve found that my heater had stopped giving out heat. In combination, I noticed it was taking an unusually long time for the car to heat up… This led me to the conclusion that the Thermostat was faulty. Even though I’d had a service recently, I thought I would drain the coolant, replace the thermostat, replace the heater valve (to the volvo one), flush out the heater matrix and flush through the cooling system a few times.

I did all of the above, noting that the thermostat was indeed stuck on open, and started her up. Still no heat coming from the heater and still taking a long time to for temp gauge to rise…

So, after a bit more searching on LEC, I thought that it could be an air lock, so left it a bit… no change…

I then saw a post on faulty water pumps… I had mine replaced in the summer (as part of the cambelt change), so thought I’d better check.

So here are the daft (amateur) questions:

I attached a hose to the pipe that goes into the heater valve (I’d closed the heater valve), then turned on the engine to see whether coolant would be pumped out. An initial burst of coolant came out, and then nothing…. When I rev’d the engine, it started to flow.. Is that normal? I though it would flow on tick over?

Now for the daft question, could I have re-hosed the car in correctly. I have the “y” pipe going into the outlet next to the thermostat housing (top) and then going into the heater valve. The heater output then goes into the pipe below the thermostat housing… I was just concerned whether I had the pipes the wrong way round?

Any thoughts would be helpful, thanks…

[NigeElan]

One additional point, if I take the cap off the coolant tank on tickover, the coolant does flow out...

[tigerdog]

Maybe a picture will help?

Screenshot_2021-01-20_13-57-57.png

[NigeElan]

Thanks Tigerdog, looks like I’ve plumbed it correctly. Back to the drawing board....

[nigelpen]

Are the heater controls working ok? not just the fan but the vacuum controlled directional flows. Also in the colder weather I find the car does take a little longer to heat up, especially at idle if waiting for the cooling fans to operate.

[NigeElan]

Thanks. The heater valve is working and I can hear movement behind the dash when I adjust the temp dial.

Today I’m going to disconnect the heater matrix out flow, run the engine to see if any coolant comes out. If that’s ok, then I’m going to investigate the heater to see if any mice have damaged the air flow guides...

[NigeElan]

So, ran the Heater outflow until coolant came out (Took a little time, but started to flow when I revd up the engine). Therefore, I figured it was full of air. Re assembled and tried the heater again. Slightly warm, but when revd, heater started kicking out some real heat. So all good... but nagging doubt that the water pump is not working efficiently...

[Tuga2112]

Maybe a picture will help?

Screenshot_2021-01-20_13-57-57.png

looking at this picture, i should be able to find out if the heater matrix is blocked with the engine off and the recirculating pump on by checking for coolant flow in the return pipe ?

[TorqueHorse]

Maybe a picture will help?

Screenshot_2021-01-20_13-57-57.png

looking at this picture, i should be able to find out if the heater matrix is blocked with the engine off and the recirculating pump on by checking for coolant flow in the return pipe ?

Maybe? I think there are a lot of "if's" in this scenario, like if the heater valve is open or closed, and if the thermostat is open or closed. Both of those affect the paths that coolant can take and depending on which "return" pipe you check, no-flow wouldn't necessarily point to the matrix.