Too hot!!!

Author
Discussion

fr3n2y

Original Poster:

210 posts

199 months

Tuesday 17th June 2008
quotequote all
My car is overheating.....alot..I can often hear bubbling under the bonnet from the expansion tank when stopped in traffic..

The father of a friend of mine had a quick look at the car yesterday and he says it appears the fan is not turning on to cool things down. I must say I haven't really noticed..... He recommended I loop the fan relay (i think thats what he said) to see if the fan turns on and find out whether its just the relay and not the actual fan thats packed up..

I was too embarrased to ask how to do it and thought i'd check with the pro's on here.

Is he right and how do i do it??

I've just ordered a new thermostat from mx5parts so hopefully this will help??

DennisTheMenace

15,605 posts

275 months

Tuesday 17th June 2008
quotequote all
On me 1.8 the fan is controlled off the sensor on the rear of the engine behind cylder no.4 if it fail the fan defaults to on all the time , check your diagnostics , with a couple of bits of wire you can check the fan etc as well

anonymous-user

61 months

Tuesday 17th June 2008
quotequote all
Conversely, the 1.6 fan is triggered by a thermoswitch in the top of the thermostat housing at the front of the engine and if this dies the fan stays off.

More details at http://www.miata.net/garage/CoolingSystemProblems....

fr3n2y

Original Poster:

210 posts

199 months

Tuesday 17th June 2008
quotequote all
Cheers Lex, surely this will help!

MX-5 Lazza

7,954 posts

226 months

Tuesday 17th June 2008
quotequote all
One thing to bear in mind - if the coolant really is boiling then you shouldn't be driving it. If you overheat the engine you can warp and/or crack the head and can seize the engine.

ALawson

7,855 posts

258 months

Wednesday 18th June 2008
quotequote all
Had the same problem on our when we got it, new thermostat sorted the problem out. About 20 quid from mx5 parts, and easy to change.

fr3n2y

Original Poster:

210 posts

199 months

Wednesday 18th June 2008
quotequote all
ALawson said:
Had the same problem on our when we got it, new thermostat sorted the problem out. About 20 quid from mx5 parts, and easy to change.
Cool, my thermostat has just arrived, £8 with gasket from mx5 parts, will change over tonight... Is it just a straight swap, anything I need to look out for?

fr3n2y

Original Poster:

210 posts

199 months

Wednesday 18th June 2008
quotequote all
MX-5 Lazza said:
One thing to bear in mind - if the coolant really is boiling then you shouldn't be driving it. If you overheat the engine you can warp and/or crack the head and can seize the engine.
Ouch, hopefully i haven't damaged anything, the drive to work is only a couple of minutes though..

I'm stupid, to clarify where exactly do I put the coolant?? Into the rad or into the expansion bottle? I'm confused as the expansion bottle has min/max marked on it and its currently well below min...

anonymous-user

61 months

Wednesday 18th June 2008
quotequote all
On the MX5, it has the older style cooling system where the radiator and engine is pressurised, the expansion tank is not and just takes excess coolant as it heats up and expands. When the engine cools, it sucks it back in from the tank. So, when you fill it up, the radiator should be full and the expansion tank should be filled to between the minimum and maximum marks. Under operation, you can expect the fluid level in the expansion tank to rise slightly, then as it cools it will return to the previous level.

As an aside, the radiator cap is a common failure item on the MX5 and most people have poor experiences with the aftermarket replacements, so always fit a Mazda rad cap.

maz8062

2,610 posts

222 months

Wednesday 18th June 2008
quotequote all
Don't mean to teach you how to suck eggs, but isn't the temperature guage indicating a hot engine. Note, if you drive the car when the guage is in the red you are more than likely to have blown a head gasket or, worse, warped the head.


fr3n2y

Original Poster:

210 posts

199 months

Wednesday 18th June 2008
quotequote all
Its never been fully into the red/H but I often hear the bubbling from the expansion tank, plus the fan problem... Hopefully the new thermostat will help.

maz8062

2,610 posts

222 months

Wednesday 18th June 2008
quotequote all
Another tip: if you have a eunos with A/c (working or not) depressing the A/c button will operate the 2nd fan. When I had a similar problem with the main fan I used the a/c fan, although smaller, to cool the engine down to good effect.

fr3n2y

Original Poster:

210 posts

199 months

Wednesday 18th June 2008
quotequote all
maz8062 said:
Another tip: if you have a eunos with A/c (working or not) depressing the A/c button will operate the 2nd fan. When I had a similar problem with the main fan I used the a/c fan, although smaller, to cool the engine down to good effect.
Brilliant didn't think of that!