Board logo

Zetec started running hotter than usual...
nre - 5/8/08 at 11:47 AM

Over the last few weeks I've noticed that the Zetec in the back of the Mojo has started running a bit hotter than it used to. I never had cooling issues before, the car would run all day at 90-95deg. I drove to Wales last weekend and it was getting up to 105deg, and would not drop significantly even if I backed right off and tootled along at 40-50mph. I have also noticed that it seems to come up to temperature quicker than before (I use the car daily to get to work so the change is clear). The fact that it seems to warm up quicker suggests it is not a stat problem?

Other info - the rad and heater matrix get hot so water is circulating. Running correct coolant mix but not changed for a couple of years. Fan mounted on back of rad and draws air through rad - fan cuts in ok. Never had previous issues in 21k miles of Mojo motoring...!

I plan to do a coolant change for starters, but do you have any other thoughts? Is it worth changing the stat while I've got it drained down? Can waterpumps give up?

Ta for the input,

Neil

saigonij - 5/8/08 at 12:01 PM

zetecs are known to have sticking thermostats. both sticking open and closed ( or partial ).

02GF74 - 5/8/08 at 12:29 PM

does seem to point to thermostat.

yes, waterpumps, like any other component can fail, in the olden days fins used to break/rust off. If you are revving the engine high and are running pump faster than it was designed for, cavitation can occurs that can eat the rotor away.

Take if off and see - it should be obvious if it is duff as all it they are is a rotor on a shaft running on a bearing.

britishtrident - 5/8/08 at 02:50 PM

Higher ambient temperature, also check the actualtemperature is as indicated, automotive temperature thermistors tend read hotter as they age.

nre - 5/8/08 at 07:44 PM

quote:
Originally posted by britishtrident
Higher ambient temperature, also check the actualtemperature is as indicated, automotive temperature thermistors tend read hotter as they age.

Yes ambients have been up but never had the prob in previous summers. Gauge reads same as separate sensor for emerald ecu...

whitestu - 5/8/08 at 08:24 PM

And I was worried when mine went up to 105 degrees stuck in traffic on the M25 when the fan wasn't working!

What rad are you using?

Stu

nre - 6/8/08 at 07:18 AM

quote:
Originally posted by whitestu
And I was worried when mine went up to 105 degrees stuck in traffic on the M25 when the fan wasn't working!

What rad are you using?

Stu

It's a <whispers> Maestro </whispers> rad which is a common fitment on a Mojo (there's not much space). If it wasn't for the fact that the car had run fine for the last 4 years I would have suspected an undersized rad... Maybe it has got a partial blockage? When I replace the coolant I will take the rad off and give it a good flush through (and the rest of the cooling circuit for that matter).

whitestu - 6/8/08 at 08:20 AM

If you do end up needing to replace it I'm using a Polo 1.0 rad, which is 430mm x 377mm. Not sure if that would fit your Mojo, but it certainly seems up to the job on mine.

Stu