Coolant Temperature - Help please!!!!!!!

Level 2 User Joined: 25 Oct 2005 Posts: 55

Hi.

Over the past 2 weeks my coolant temperature gauge has been playing up. It warms up as per normal, then after the first marker (1/3 ??) it climbs during motorway driving to the next marker (2/3 ??), but as soon as it hits the marker (2/3 ??) it falls sharply back to the first marker (1/3 ??). This cycle repeats itself over and over again every 2 mins or so.

I'm thinking that maybee the CTS?? is playing up allowing the coolant to circulate only when the temperature reaches the 2/3 marker, allowing cold coolant from the radiator to bring the coolant temperature down drastically, before the valve shuts again and the temperatures build up again.

It never used to do this...

Any suggestions?? Wink

Level 10 User Joined: 27 Apr 2005 Posts: 620

my 205 does this i just drops 2 notches in a split second, i found it was the wires on the connector that goes to the sensor try that and see what happens only a suggestion Wink

Level 2 User Joined: 25 Oct 2005 Posts: 55

ok, thanks!

will try this...

Site Subscriber Joined: 29 Dec 2004 Posts: 395

Airlocks in the system or dodgy thermostat.

Mine did this when there was an airlock.

Level 2 User Joined: 25 Oct 2005 Posts: 55

mmm, could be an air lock then. thermostat looks ok, but no way of telling!

qu : how do i properly bleed the system to remove all air locks?

pics would be appreciated.

i thought i did bleed the system recently...but maybe not. Confused

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

thermostat, it heats upo then opens, you sure you never put it in backwards like brun did?

Level 2 User Joined: 25 Oct 2005 Posts: 55

na chris it aint been out afaik!

tis a stange one. only things that have been changed in the last few months are :

bottom and top coolant hoses
coolant system flush

This problem only started about 3 weeks ago IIRC. ???

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

Mine used to do this exact same thing.

I put in a new thermostat, sorted.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

aye, sounds like the old one is getting slow to respond.

Level 2 User Joined: 25 Oct 2005 Posts: 55

sounds like (yet) another thing to keep me busy at the weekend then!

are they cheap to buy?

Wink

Site Subscriber Joined: 29 Dec 2004 Posts: 395

few quid

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

under a fiver from a factors, 20 quid fropm ren or 12 quid from halfords!

your choice!

Level 2 User Joined: 25 Oct 2005 Posts: 55

cheers!

its been ok last couple days Confused

but i aint been on the motorway. will see next time im on the motorway... Wink

Level 2 User Joined: 25 Oct 2005 Posts: 55

ok...its still doing it! is it possible/likely that the gauge isnt working properly or is it defo gonna be the thermostat? surely when the coolant is hot enough the thermostat will open....and then stay open until you turn the engine off? It wont keep opening and shutting? Confused

Level 3 User Joined: 10 Oct 2005 Posts: 66

Quote:

The thermostat is an important component on any engine, especially a high-performance one. It closes when the water temperature is low (cold) to prevent the water from circulating in the engine and opens when water temperature is high (typically above 180 degrees) to allow circulation through the system. Without a thermostat, the water would simply circulate too quickly and possibly even reduce power partly because more horsepower is required to drive the water pump when the restriction of the thermostat is removed

Retroholic Joined: 23 Dec 2005 Posts: 3315

ooooo better fix mine to then lol

Site Subscriber Joined: 28 Jan 2005 Posts: 3547

actually the temp is more around 80deg when the stat opens.

Cockney, where did you find that quote?

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

danlp6 wrote:

actually the temp is more around 80deg when the stat opens.

which is about 180deg fahrenheit Rolling Eyes

danlp6 wrote:

Cockney, where did you find that quote?

Off some american website, I'll bet Wink

Level 3 User Joined: 10 Oct 2005 Posts: 66

Yep indeed Neal, http://chevyhiperformance.com/techarticles/148_0504_how/
Forgot to change it from Fahrenheit to Celsius, but correctly answered stew punkâ€™s question none the less,

stew_punk wrote:

surely when the coolant is hot enough the thermostat will open....and then stay open until you turn the engine off? It wont keep opening and shutting?

But next time ill stick to UK Territory when trying to answer questions
Laughing

Site Subscriber Joined: 28 Jan 2005 Posts: 3547

This bit made me laugh!

Quote:

because more horsepower is required to drive the water pump when the restriction of the thermostat is removed

Level 2 User Joined: 25 Oct 2005 Posts: 55

ok guys...

fitted new thermostat today and problem hasnt gone away!

(cheers chris for the quick question over the fone!)

Car warms up fine....fan kicks in when it should (about 2/3) BUT when driving at constant steady speed the coolant temp gauge goes from 1/3 to 2/3 and back again every minute or so.

Its obviously not the stat then! What could it be?

Cheers,
stew