Water problems

Archives of Posts to the NZ MX5 List back in 2006
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Mikkels
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 140
Joined: Sun Jul 02, 2006 9:04 pm

Water problems

Post by Mikkels » Mon May 15, 2006 9:57 pm

I have been chasing an overheating problem for a year now.
I think I have a moving target. Symptoms are overheating
under load when fully hot. Usually happens going up the
Bombay hills at 100k on the way south. uage climbs and may
reach H but quickly returns to normal on ordinary driving.

I have re - cored the radiatoe to a brand new double core
(will be good for FI when I get there). Replaced thermostat
and cap plus a couple of hoses when the engine was out to do
the flywheel.

On the last occasion there was loss of water (first time I
have seen that happen. No leaks on the garage floor though.
The other thing I noticed is a fine white powder deposit
all over the engine after the last run.

Ideas please. I thinking water pump (seal perhaps gone but
how to tell) Head gasket - I can get that tested at a
garage I guess by them doing the water test for carbon
monoxide.

Once I have a diagnosis I can fix the @#%$$ thing.

Don
1.8 in a 1990
1990 NA with a 1.8 conversion SOLD
2005 NC Limited edition 2470/3500 6MT

David Moughtin

Water problems

Post by David Moughtin » Mon May 15, 2006 10:26 pm

Some time ago I had a water leak, the source of which I found I found by
accident. I found that by reving the engine with the bonnet raised I could
see a fine jet of water spraying from a tiny hole in one of the pipes. The
only reason that I could see it was that it was against a dark background -
the closed garage door.

Regards


David Moughtin

KSCRIM
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 137
Joined: Thu May 18, 2006 8:46 pm
Location: West Auckland

Water problems

Post by KSCRIM » Mon May 15, 2006 10:51 pm

Probably a head gasket blown, worst case a pinhole corrosion perforation in
the alloy head somewhere. (Writing from some experience with alloy engines,
65 Hillman Imp). Cooling system can cope with normal driving but unable to
cope with extra heat caused by full power operation.
Could be the water pump impeller or case corroded, or something as simple as
a loose belt and the water pump slipping??
Another thing, Have you got the heater connected up? or if not, is there a
connection across the hoses at the rear of the block that would normally go
to the heater. The water flow has to go through these hoses to get correct
water flow around the head and block, otherwise # 4 cylinder overheats. The
temp gauge sensor is at the back of the engine.

Is the cooling fan working? For cars with A/C, when the A/C is on, both fans
run.

Ignition timing correct?

Coolant losses usually leave a telltale mark of white or green powder as the
water evaporates on the outside of the block. Can give an idea as to where
the leak is. The white powder you mentioned is probably from coolant, and
may well be from the waterpump seal. An overtightened belt can destroy the
pump bearings, leading to seal failure and poor circulation of coolant,
leading on to other failures, (head gasket).

Kevin

[...]

From ben.nakagawa@gmail.com Fri Apr 27 17:59:56 2007
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Date: Mon, 15 May 2006 23:06:34 +1200
From: "Ben Nakagawa" <ben.nakagawa@gmail.com>
To: MX5List <mx5list@mx5club.org.nz>
Subject: Re: Water problems
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That white powder thing is a coolant leak dried in the hot engine bay.
I had smiler (small) one around heater core hose and replaced. ( I was told
this was pretty common for old -MX-5)

I suggest all the horses, if you see the white substance where the horse is
connecting, replace the hose and may be clips as well.


I never experienced over-heating through.

On 5/15/06, mikkels@ihug.co.nz <mikkels@ihug.co.nz> wrote:
[...]

--
Ben Nakagawa
Ben.Nakagawa@gmail.com
Kevin 2010 NC PRHT. (98 NB6C sold)

Mikkels
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 140
Joined: Sun Jul 02, 2006 9:04 pm

Water problems

Post by Mikkels » Tue May 16, 2006 7:08 pm

Happy to fix whatever it is once I know. The fans both work
OK and the heater is plumbed as normal. One thing I have
noticed is gurgling through the heater system which
indicates air in the cooling system. This comes and goes
but could be combustion gases (head gasket or just a leak
somewhere.

I like the theory about the water pump. I'll slip off the
belt and the fron pully for the pump to see if I can see any
signs of leakage there.

Cheers

Don

[...]
1990 NA with a 1.8 conversion SOLD
2005 NC Limited edition 2470/3500 6MT

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