Running Cold

[Griffinr]

My S3 just does not get warm this weather, did 100 motorway miles yesterday and the gauge sat just on top of the white band at the bottom of the scale. It does come up a bit more at slow speed or if you tick over stationary but at speed stays cold. Thermostat has been changed twice and tests out OK. Now thinking of partially blanking the rad or the front grill for the winter, has anybody found a satisfactory way of doing this.

Rob.

ps. It was fine all last summer.

[Griffinr]

Barkychoc said:

Presumably heater is hot?
Could be temp gauge sender quite a common fault on the fords the engine came from.

Heater is barely warm, temperature does come up if you allow it to tick over for a while so the gauge and sender are OK and both the stats I have had fitted tested ok. There seems to be quite a lot of circulation into the rad even with the stat shut, this is through the smaller hoses that go into the swirl pot.

Rob.

[Griffinr]

Jed-S said:

I'm begining to think that the design of the cooling system is flawed but haven't had a chance to look at the coolant flow on the donor vehicles.

I think there is a flow diagram in Steve Heaths book, I'll have a look tonight and see if I can work it out.

[Griffinr]

tozerman said:

I have always wondered about this,what I think is causing it is the pipe that goes from the water pump straight to the swirl pot and obviously then to the radiator thereby missing the stat altogether and causing longer warm up times !!!
Cheers.....Tony..

My thoughts also, I wonder where this pipe went to on the granada? I'll have a look in that manual too.

[Griffinr]

Jed-S said:

I wouldn't bother looking - it isn't worth the paper it is printed on. It doesn't even have a swirl pot on the diagram.


Maybe it is time to re-plumb the car and get rid of the swirlpot and fit a header tank in its place. If the pipe from the thermostat housing goes straight to the upper rad pipe and the small 10mm (?) pipe from the pump goes to the lower rad pipe and also has a T that goes to the header tank. That's my initial thought from the warmth of my living room but it might have to change when I get my head under the bonnet again.

I think your right, reading the Granada manual it appears that the water pump bypass pipe goes to the header tank. The feed from the header is them connected to the bottom of the rad. My thinking is to put a tee into the bottom hose to take the bypass and then blank off the spare connection on the swirl pot. Bit of a tortuous pipe route though.

Rob.

[Griffinr]

tozerman said:

Trying to think about it logically, the only way this hose can be justified is if on a granada it goes straight to the radiator, the only way to be sure is to try it without that hose connected and the two 16mm unions blanked off and see what happens although I'm not brave enough to try it

Cheers.....Tony..

I think it is required to take the load off the pump when the thermostat is closed.

Rob.

[Griffinr]

Thanks for the replies, I think we have established that all the V6 cars run too cold in the winter if the rad and water system are in good condition. I’m also pretty sure that this is due to the bypass hose being connected to the swirl pot. I will have a closer look at the weekend (weather permitting) and maybe try a bit of re-plumbing. Will keep you posted.

Rob.

[Griffinr]

macL said:

Try a Low Tech Solution

That was my first thought till I decided to look for the root cause. Might end up back there yet, will let you know.

Rob.

[Griffinr]

Well, been doing a bit of under bonnet plumbing this weekend following on from my theory that TVR got it wrong. I have now removed the water pump bypass hose from the swirl pot and blanked off the swirl pot connection. I have brazed a 16mm pipe into the steel link pipe in the bottom hose and connected a longer hose from the pump bypass to it.
The car now warms up to normal (middle of the gauge) in 6 minutes and stays there regardless of speed. Not sure how it will perform in the summer but have a plan B using a bypass thermostat just in case I get over heating.
Amazing how well the car runs when its at the right temperature.
Also discovered that the fan was wired back to front, don’t know if that was original or a previous owner.
Rob.
(edited for spelling)

Edited by Griffinr on Sunday 6th February 21:06

[Griffinr]

Jed-S said:

I clamped off the 5/8" hose from the pump to the swirl pot as a test

Jed

Ok as a test with the heater valve open but I would'nt leave it like that.
Mines also up to temp in about 2 miles, it will be interesting to see what effect it has on fuel consumption as its always run too cool in all but the hotest weather or very hard driving.
Just need to see how it copes with the hot weather now. If I get a problem I will add a second (remote) thermostat to direct hot pump bypass water back to the swirl pot.

Rob.

[Griffinr]

Now been running for 2 weeks with the modified cooling system and no problems. Up to normal temp in 2 miles and stays there just like a normal car. Edges up a bit in slow traffic but the fan hasn't cut in yet so am hopeful it will cope in the summer. Running and sounding much smoother, and the heaters brilliant.
Petrol gauge seems less inclined to head south also.

Rob.

[Griffinr]

Just thought I'd post a update on the cooling system mod now we've had some warm weather. Car is still behaving itself, the fan has still not cut in at all in normal use. Done a check on the fuel consumption and am now getting 32mpg on local running around town (I was getting 22 over the winter before I re-routed the bypass hose. Well pleased.

Rob.