Cooling system problems? Could use expert opinions!

Cooling system problems? Could use expert opinions!

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NiceCupOfTea

Original Poster:

25,305 posts

257 months

Tuesday 2nd June 2009
quotequote all
Had the water pump replaced on my MX-5 earlier in the year to cure a leak.

Ever since then there has frequently been a smell of coolant about the car. It hasn't concerned me too much as it doesn't seem to be losing coolant. At most the level has gone from max-min over several months.

Today was sitting in traffic, very hot day. Engine temp rock solid in middle of guage. Parked up and could hear fizzing under the bonnet. Popped it, and it seemed to be coming from the top-up tank. Level was max (sure it was just above min when I checked on Sun). Bonnet was too hot to hold and burned finger - but car is black and sun was beating down.

Rad cap new in last year. Haven't checked rad coolant level since but was brimming on Sun.

To sum up, temp guage reads normal, don't seem to be losing much (if any) coolant, but something was very, very hot and I can smell coolant. No obvious leaks or splits.

Help!

vrooom

3,763 posts

273 months

Tuesday 2nd June 2009
quotequote all
have a look at top of rad, or bottom themostat housing pipe...




NiceCupOfTea

Original Poster:

25,305 posts

257 months

Tuesday 2nd June 2009
quotequote all
Is that a crack?

anonymous-user

60 months

Wednesday 3rd June 2009
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Both my mk1s have a coolant smell about them when stopped after a run, I think this is because the cooling system is not sealed. Certainly neither are using any coolant or having any problems, so I think that's just normal. It's not a strong smell though, just a few wafts as you walk around the car.

You can normally spot coolant leaks as they leave behind a white residue - mine leaks slightly from the thermo housing gasket - the thing is caked in white crustiness but it's only lost about a thimble of coolant in 6000 kms - if you've lost loads it should be obvious where it's landed. Have a check around of all the pipes - specifically check those two that go into the heater through the bulkhead and the metal t-piece under the thermo housing.

Check the level under the rad cap also - apparently (accordind to the owners club) you're not supposed to rely upon the expansion tank level as an indication of what's going on.

Edited by anonymous-user on Wednesday 3rd June 08:04

swansea v6

1,281 posts

231 months

Wednesday 3rd June 2009
quotequote all
I had exactly the same smell from my black, mark 1 Eunos, after a long run, or just sitting in traffic on very hot day, you would get a waft of coolant....never used any and never overheated, so they must all do it???

MX-5 Lazza

7,952 posts

225 months

Wednesday 3rd June 2009
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The rad would have been removed to change the water pump (did they change the cam-belt at the same time?) so check the top & bottom hoses are not leaking. If it still has the old steel spring-clips on the hoses replace them with jubilee clips - the spring clips don't like being removed/replaced and lose their spring.

NiceCupOfTea

Original Poster:

25,305 posts

257 months

Wednesday 3rd June 2009
quotequote all
No cracks on the rad top but there do seem to be a lot of tiny stress marks. Had a quick search on the MX5OC forum, suggestions are for all sorts, inc radiator, airlock, stat...

Odie

4,187 posts

188 months

Thursday 4th June 2009
quotequote all
So basically the problem is that you can smell coolant?

Drain coolant, put in odourless coolant.

Sorry i know thats silly, check you have the right pressure rated radiator cap (or get it pressure checked to make sure its not faulty)

Edited by Odie on Thursday 4th June 13:36

NiceCupOfTea

Original Poster:

25,305 posts

257 months

Thursday 4th June 2009
quotequote all
I can smell coolant and the coolant in the top up tank is boiling.

If I can smell coolant constantly something ain't right! It has had a brand new genuine Mazda radiator cap within the last 6-12 months.

bluetone

2,047 posts

225 months

Friday 5th June 2009
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NiceCupOfTea said:
I can smell coolant and the coolant in the top up tank is boiling.

If I can smell coolant constantly something ain't right! It has had a brand new genuine Mazda radiator cap within the last 6-12 months.
Have you checked your rad fan is working?

http://www.miata.net/garage/CoolingSystemProblems....

(I will be doing this on my car tonight as it goes..)

NiceCupOfTea

Original Poster:

25,305 posts

257 months

Friday 5th June 2009
quotequote all
Not recently - will do the TEN/GND accelerator test later. Did have the air con (with associated fan) on though I think.