Is my thermostat stuck open?

[Jimm218]

Hi All,

I'm wondering if my stat is stuck open and wanted to compare the readings I'm seeing with other peoples.

On my 4.2 last night at 70mph both temp readouts were giving 75C and weren't getting any higher. Slow down to 50mph and it might creep to nearly 80C. Heaters weren't blowing much warm air into the cabin either so I'm fairly sure the stat is lazy (which would make 3 of my 6 cars with the same issue!)

What are other people seeing this time of year?

[CerbWill]

I'm sure there's some aftermarket thermostats that open in the 75-80 degree range. Might be you have one of them fitted.

[Jimm218]

Its possible I guess but I think it is an original. Don't recall anything in the paperwork to suggest it has been changed.

[Jhonno]

In this weather it is a little cold, but not massively.

[gruffalo]

When mine was stuck open it struggled to reach 60 when cruising in the winter, 75 sounds ok.

[Chim450]

On my Speed 6 Tuscan the water Temp was reading 75 on the Motorway and mid 80s in traffic the other day. So yours sounds about right.

[Byker28i]

I was seeing around 80 on the gauge last month on a cold day on the motorway, around 85 in traffic, but I've done a lot of work to keep mine running cool as we take it abroad. Last year it was 40C on some days and it coped fine.

[assynt road]

If the engine temp is falling when you drive in cold weather the thermostat is stuck, or at least not closing again when temps drop. It’s a quite common problem had it with a few of my cars over the years including the Cerb.

[Jimm218]

Thanks all. Sounds like it is close to normal. I might change it next time it is all apart to see if it makes any difference.

[Mr Cerbera]

I always ran at approx 75°coz I didn't know any better (and my Service engineers didn't spot it)

When I went to Jools for Whirlwind and Coolchip installation, he noticed that it shouldn't be that consistently low and found a jammed open thermostat.

Since fitting the new one, she will always get into the 80s after 15 mins and then run to Jools' coolchip settings before the fan/s kick in and reduce the temps to the preset levels - 82 and 88 IIRC (haven't driven her for 2 years )

_Adendum_
I don't run her in Winter months so have no idea if she'd reach the 80s when the ambient is 2°.

HTH

Edited by Mr Cerbera on Thursday 27th February 12:15