Temp needle up and down???

[The Chubby Pirate]

Replaced the coolant temp sensor (right hand side on block) and the needle is still rising and falling?

There doesnt appear to be any actual issue but it still makes me worry?

its a Phase 1 172 btw.

cheers

 

[The Fatty]

could be the thermostat getting stuck and only opening when if gets really hot i suppose?

 

[Rob]

That's what I was about to stat, thermostat starts to go, (or if it's always done it, someone's fitted the wrong one), so it's getting way above regular temp before it opens, the water's circulating, cooling it, it's closing, and repeat.

 

[The Chubby Pirate]

Hmm, its defo an original going by the shape of the pipes etc.

Anyway to strip it down or is it better to replace?

 

[Rob]

It's cheap as chips to replace mate, you can't see the thermostat to see if it's original or not though.

It'll need a decent coolant fill up but it's not a hard job.

 

[Rob]

http://www.eurocarparts.com/ecp/c/R...931cd8a08a6d4f88f97d595442e7722b4a23da&000325

Then type "PARTS25" at the checkout at get another 25% off.

 

[The Chubby Pirate]

Ahhhh i see! I was mis led!

Is this inside the metal housing to the right of the engine? (Near the coolant sensor is?)

cheers Rob!

 

[Rob]

That's the one, three bolts to get it out iirc.

The bleed screw is the bolt on it. Personally I'd just open bleed screw and bleed into a funnel going somewhere, unbolt thermostat housing, remove thermostat, replace thermostat, re fit thermostat housing, re fit bleed screw, fill up, undo bleed screw a bit to check you've not randomly trapped some air, and refit.

Then just run it up to temp with the cap off, wait for the stat to open, then fill it up if it needs some.

 

[The Chubby Pirate]

Just use new coolant i gather aye?

I'm almost certain im going to f**k this up is there a guide anywhere?

 

[Rob]

Think there is mate yes, and if there's not one in the guides section, a few have written out the process better than I just did quite a few times before.

 

[Jonnyf007]

That will be your thermostat had the same issue on mine, replaced the cts and thermostat now runs perfect no issues with the needle gauge got my both parts from renault as i always get my parts from there part no for the thermostat should be 8200772985

 

[The Chubby Pirate]

I gather its in here;

(note the shiny new temp cooler)

???

 

[wrc172]

I honestly wouldn't have thought a fault thermostat would cause that symptom.

At what points does it mainly rise/fall on the gauge?

 

[Jonnyf007]

Yes, not the three side bolts you see in the image plain but there are three more, you can see one of the three bolts head on. One of them looks a bit bronzy on the front there! Thats one of the three to access the thermostat. The other one is just under it you will have to move some of the grooved cable cover next to the big pipe to see the other one on top. But fairly easy spottable.
If that makes sense lol.

 

[The Chubby Pirate]

Randomly mate, sometimes it doesnt happen for a few days then it does. Like i say, it has no effect on the car performance wise.

It will affect MPG though as i would imagine, i give it pretty much 10/10ths everywhere so if something was going to break it would have by now?

 

[The Chubby Pirate]

Yes, not the three side bolts you see in the image plain but there are three more, you can see one of the three bolts head on. One of them looks a bit bronzy on the front there! Thats one of the three to access the thermostat. The other one is just under it you will have to move some of the grooved cable cover next to the big pipe to see the other one on top. But fairly easy spottable.
If that makes sense lol.

Cheers Jonny, yeah i know the three bolts you mean! I gather the bolt furthest to the top on the side is the bleed one as it doesnt seem to be holding anything in if my amatuer mechanics serves me right lol

 

[Jonnyf007]

That's the one
hope it goes well for you , be careful that you don't drop any of the bolts down the engine bay :/

 

[The Chubby Pirate]

haha, i've been that soldier once too many times in the past lol..

 

[Djw John]

Always gonna be one or the other Danny, if one has been replaced the other will need done in time anyway.

 

[The Chubby Pirate]

Aye John you're right!

I'll no doubt text you tomorrow when i make an arse of this lol...

 

[The Chubby Pirate]

I gather this is better to do when the car is cold? Also, how are people catching the coolant that im likley to lose as a result of taking this apart?

 

[.GAZ.]

Dump it down the drain. FFS!

/Homo.

 

[Munson]

The dealer that fixed my temp sensor issue said that the fault was a wiring problem at the sensor. Not the sensor itself.

 

[The Chubby Pirate]

Dump it down the drain. FFS!

/Homo.

Read it again you spastic! Catch the coolant not dispose of the coolant!

PRICK.

 

[Rob]

I mention that in my post. Funnel and a bit of hose.

 

[The Chubby Pirate]

Does alot actually come out? Cheers Rob!

 

[Rob]

Nah, just like you taking a piss after a few beers, small flow, long duration.

 

[Munson]

Is the needle flicking up and down quickly?

If it is, srsly don't waste your time on the thermostat.

 

[J203425]

Is the needle flicking up and down quickly?

If it is, srsly don't waste your time on the thermostat.

This.

Don't want to alarm you but if its going up and down really quickly check the head gasket. I had this on a 205 gti year's ago and head gasket was leaking gas into the coolant intermittently and causing temp spikes.

 

[MicKPM]

Deffo a cooling circuit fault that. There's no way a stat would make it jump as described if it was faulty.

My guess is massive airlock, faulty CTS (unlikely) or head gasket due to incorrect maintenance.

Mick

 

[Djw John]

It's the head gasket Danny, I'll be round with £100 and a towbar tonight

 

[Rob]

He doesn't say rising and falling really quickly does he?

He just says rising and falling? So I though maybe, car gets warm, car gets warmer than usual, finally stat opens, temp drops down, stat closes, repeat?

 

[Munson]

Possibly. I only asked a question. We don't yet know the answer TBH.

 

[The Chubby Pirate]

I dont know where people are getting the needle going up and down rapidly from, it does it once every few weeks, it'll rise slowly then come down to half way again.

It gets driven at 10/10'ths absolutley everywhere, there is nothing wrong with the head gasket. :S

For anyone interested, its all good now, even with my panther like reactions some of the coolant managed to escape so i went to Reno and bought some Type D and topped it up, all is well and good in the world with the green machine;

 

[MicKPM]

Result

 

[The Chubby Pirate]

Just went a wee drive, seems the issue still exists LOL.

What else can/should i check? The thermostat and coolant sensor have both been changed, bearing in mind there isnt an actual problem to report of??? Car drives fine/no smoke etc??

 

[Dan519]

is the cambelt due? might be in need of a water pump, seen an odd issue like this and found a couple of impellars broken off the pump. Was a bit weird

 

[The Chubby Pirate]

It is actually Danny aye!

End of the month? Is there anything else you could think it would be?

 

[Dan519]

need to pay attention to if the rad fan stays on more often that you'd expect, if you're using the heating in the car more, general things like that. Doesn't sound very serious though, just varying temperature.

 

[wrc172]

Might be bett if you can explain exactly when it happens? More often when you are driving on motorway etc? Or in traffic?

There is only a few realistic things it can be.