MGZR 1.4 issues, any experts?

[andymc]

Hi all.
just took in part ex and if im honest I could have been more thorough on the check, drove the car for 15 miles and couldn't get the temp gauge to move off bottom, the heater is just chucking out cold air as well, the coolant level is fine and there is no white smoke or mayo in the filler cap, the car is not showing any signs of over heating or gasket failure, can anyone point to a remedy?
thanks (head gasket was done last year)
Andy

[MGZRod]

Thermostat?

[andymc]

that's what i'm possibly thinking, it was blowing hot air originally but the chap says its now cold only

[maxdb]

I am certain that would be a thermostat issue.

[davepoth]

Water pumps can be iffy on these too, but I'd have thought a complete failure would have resulted in more of a problem before now.

My guess is that you'll find that the thermostat has been completely removed to mask an overheating issue.

[andymc]

davepoth said:

Water pumps can be iffy on these too, but I'd have thought a complete failure would have resulted in more of a problem before now.

My guess is that you'll find that the thermostat has been completely removed to mask an overheating issue.

if thats the case am i to assume its shagged

[Auntieroll]

Not necessarily, the 'stat may just have failed " open". Fingers crossed !

[andymc]

I am tempted to agree (fingers crossed) as the engine would cook after prolonged use I assume?

[CraigyMc]

andymc said:

Hi all.
just took in part ex and if im honest I could have been more thorough on the check, drove the car for 15 miles and couldn't get the temp gauge to move off bottom, the heater is just chucking out cold air as well, the coolant level is fine and there is no white smoke or mayo in the filler cap, the car is not showing any signs of over heating or gasket failure, can anyone point to a remedy?
thanks (head gasket was done last year)
Andy

Sounds like the thermostat's fked. The good news is that the part is not too pricey (usually under £10).

[andymc]

CraigyMc said:

andymc said:

Hi all.
just took in part ex and if im honest I could have been more thorough on the check, drove the car for 15 miles and couldn't get the temp gauge to move off bottom, the heater is just chucking out cold air as well, the coolant level is fine and there is no white smoke or mayo in the filler cap, the car is not showing any signs of over heating or gasket failure, can anyone point to a remedy?
thanks (head gasket was done last year)
Andy

Sounds like the thermostat's fked. The good news is that the part is not too pricey (usually under £10).

Craig, is my assumption correct that with extended use the car would have cooked itself if the thermostat had been removed to hide temp issues?

[CraigyMc]

andymc said:

CraigyMc said:

andymc said:

Hi all.
just took in part ex and if im honest I could have been more thorough on the check, drove the car for 15 miles and couldn't get the temp gauge to move off bottom, the heater is just chucking out cold air as well, the coolant level is fine and there is no white smoke or mayo in the filler cap, the car is not showing any signs of over heating or gasket failure, can anyone point to a remedy?
thanks (head gasket was done last year)
Andy

Sounds like the thermostat's fked. The good news is that the part is not too pricey (usually under £10).

Craig, is my assumption correct that with extended use the car would have cooked itself if the thermostat had been removed to hide temp issues?

Depends on which way it broke. In my experience of the K (elise) it failed open, so took fecking ages to warm up.

There's a fairly straightforward test to check which way it's going. Start the engine from cold, and figure out which bits are getting hot and which are not.

[Auntieroll]

No, if the 'stat fails "open" then the bulk water temperature may never/take ages rise to the normal temp, Especially at this time of year.
The R25 heaters are not the best in my experience so a 'stat that opens at a slightly higher temp is preferable to give a quicker cabin warm-up ie 92C instead of 88C

[CraigyMc]

If it was done on purpose, there are several things that might have been done.

(a) thermostat knackered
(b) temperature sender broken
(c) heater matrix no longer part of circuit (either on purpose or full of post-HGF gunge)
(d) heater matrix has simple airlock
(e) water pump failing/failed
(f) something in the PRV is screwed

Any of the above could be true. Needs a small amount of testing to figure out what's what.

[CraigyMc]

Auntieroll said:

No, if the 'stat fails "open" then the bulk water temperature may never/take ages rise to the normal temp, Especially at this time of year.
The R25 heaters are not the best in my experience so a 'stat that opens at a slightly higher temp is preferable to give a quicker cabin warm-up ie 92C instead of 88C

I think the "No" in this was due to posting lag since we agree on the mechanism in play.

[Auntieroll]

CraigyMc said:

I think the "No" in this was due to posting lag since we agree on the mechanism in play.

Agreed, either way, I'm glad its not me having to mess around under the inlet manifold to fit another thermostat!

Agreed a good flush through is a good idea though, particularly if the matrix has not been cleaned properly after the HGF.

[andymc]

So after the many and welcome replies can I assume the H/G isn't shagged as there is no white smoke, mayo in the filler cap or a boiled engine

[nipsips]

Check the heater valve it no doubt will be shagged if there are no other issues.

[andymc]

so is the H/G ok?

[andymc]

quick bump

[davepoth]

andymc said:

so is the H/G ok?

Well, it depends. It's entirely possible that if the thermostat was removed it was done before the HG was done. In that case it could well be fine. Either way, the thermostat isn't working so I'd swap in a new one since they're cheap; it'll probably fix it straight away.