MX5Ireland

Hi all,

I done some work recently to my 5 - replaced the timing belt and
replaced/flushed the coolant.
My problem is this - the coolant temp is normal at idle and up to around 100 km/h
on the road. But when I exceed 100 km/h the temp needle rises from half way
to around 3/4 mark. Sometimes even higher to not far off the red limit. The
ancilliary belts all seem tensioned correctly and I can't seem to find any air lock in
the system.
Any ideas ?

Also recently I started to feel a judder coming up through the gear stick at
certain rpm i.e. 2000 rpm in 4th gear, 3000 rpm in 5th gear.
Has any of you ever experience this ? I've only noticed this occurance ove the
last few days.

Mark.

Hi Mark

Dunno about the judder, but the overheating problem could be

1. fans aren't plugged in or are damaged. To test, get the engine hot and see that they are spiinning fast.
2. thermostat is jammed and needs replaced
3. airlock in the system after you refilled it - easily fixed: put the heater controls to full-hot, remove the radiator cap and run the engine for a few minutes - if you see bubbles, then that's the airlock working its way out. Put that rad cap back on and get the engine hot enough to have the radiator fans running, put on some thick gloves and give the pipes to and from the radiator a squeeze

My money is on #3 !

is the rad cap in good working order?

if you have AC stick it on and the fan inside the car. Bother fans should come on
ground the fan temp switch which is the one on the top rad hose and see if the fan works.

The let her get warm and see if the fan kicks in.

Hi guys,

The temp switch is brand new as I replaced when doing the previous work.
I checked to see if the fans work and they seemingly do - one fan comes on
due to the fan switch and the other fan comes on with the A/C.
I thought I bled the system correct but maybe I do have an air lock problem.
Mind you, I didn't notice any air bubbles in the system but I'll try it again.
The rad cap seems to seal ok.

As an update to this, the bottom rad hose was cold hence a blockage. The
blockage took the format of a defective thermostat. I fitted an 82 degree
thermomstat and the car runs perfectly now.
Now to attack that weird judder...........

nice one!

[web_site][/web_site]

Cause of judder found: worn spicer/universal joint on the prop shaft. Ordered a
good used item from Autolink in the UK (£23 excl. delivery). Mazda will only
supply a complete prop shaft (mental money apparently) and not the universal joint.

93 Mk1 wrote:[web_site][/web_site]

Mazda will only
supply a complete prop shaft (mental money apparently) and not the universal joint.

now THERE's a surprise

John

Well I hope to have the replacement prop shaft this week so hopefully that will
be another job off the list once I fit it. I'm slowly getting to know my car inside
out (literally) !
Oh, a tip for ye ! I had to replace the heater hoses as they were getting old.
It's around €25 for one from the main stealer but Autolink in the UK will sell you
kevlar reinforced hoses for £17 excl. VAT for the pair. I imagine these should last
years.

93 Mk1 wrote:[web_site][/web_site]

Cause of judder found: worn spicer/universal joint on the prop shaft. Ordered a
good used item from Autolink in the UK (£23 excl. delivery). Mazda will only
supply a complete prop shaft (mental money apparently) and not the universal joint.

Cool!
How did you discover it was the prop shaft?

I had access to a ramp. There was what seemed way too much play in the
spicer (universal) joint. After checking the symtoms of a worn joint, it tied in
with my own problem i.e a judder at certain revs and also an intermittent
squeaking noise. And recently a banging noise while changing gear under hard
acceleration (due to the play in the universal joint).
It's the first time I've ever had trouble with a prop shaft on a car so it was a
learning curve for me.