overheating problem

Post by **dennis** » Thu Jun 26, 2003 8:24 pm

hi all
i wonder if any one can help me on this one.
my 1098 engine is overheating and losing a bit of water.
this has happened over the past 2 weeks.
i replaced the bypass hose and bottom hose, i have checked the thermostat and it opens and closes.
there is no lack of power or undo noises.
when i take the rad cap off, on my othere engines i can see the flow of water, i fitted a water [pump about about 15 months ago, could this still be the problem.#

Post by **dennis** » Thu Jun 26, 2003 9:23 pm

just to update a bit on this.
i have filled the thermostat housing with water and turned the engine over via the solenoid and the water rises out of the thermostat housing slowing, would have thought it would have come out faster, could it be the water pump?.
thanks in anticipation.

Post by **Cam** » Thu Jun 26, 2003 9:24 pm

Have you tried flushing the radiator and engine block. If not then try flushing both and in both directions until the water runs clear.

By doing this, if you only get a trickle out you have found your blockage. might as well flush the heater matrix while you are at it.

Post by **dennis** » Thu Jun 26, 2003 9:26 pm

thanks cam i will try that the weekend.
i do not want to sound thick but how is this best done.
thanks

Post by **Cam** » Thu Jun 26, 2003 9:47 pm

The radiator is easy. Just disconnect the top and bottom hoses and put a hosepipe in whichever end and seal it with your hand then watch the other end until it runs clear. Then swap ends.

The engine works best if you remove the thermostat and put the hosepipe in the top of the thermostat housing and watch the bottom radiator hose for the clean running water. Then swap over. Put the hosepipe in the bottom radiator hose and watch the water coming out of the thermostat housing.

For the heater matrix, disconnect the two rubber pipes going to the engine (heater tap and copper pipe next to spark plugs) put the hose up one and watch the other. Then swap over when it runs clear.

You might find that the heater matrix cleans itself when you flush the engine, but do it separately to make sure.

Post by **dennis** » Thu Jun 26, 2003 9:57 pm

many thanks cam

Post by **paulg** » Fri Jun 27, 2003 10:39 am

If the above doesn't work (it probably will) it is worth checking the external condition of the radiator.
I had a similar problem - did all the usual things as above but they made no difference. The solution was to replace the radiator! The little feathery bits of metal that diffuse the heat had mostly fallen off and I didn't realise just how important they are. The radiator couldn't cool the water enough.

Post by **dennis** » Sun Jun 29, 2003 5:52 pm

hi
tried all the above.
no blockages, so that was ok, checked radiator although it was a new one fitted last year.
ok so took it for a spin today and still overheats.
could it be the thermostat not working properly.
what one do you guys use, i have a 1969 1098 .
thanks

Post by **Cam** » Sun Jun 29, 2003 11:13 pm

I think mine is an 82 degree one.

Have you checked the carb settings (too lean) or timing. I think if your cooling system checks out, it may be time to start looking elsewhere.........

Post by **grainger** » Mon Jun 30, 2003 12:13 am

hi

when you say its overheating, how do you know ? is it running on ? or are the spark plugs white ? or is it just boiling a bit of water off in the hot weather ?

do you use optimax petrol ?

cheers
grainger

Post by **Shmickle** » Sun Jul 06, 2003 6:52 pm

I feel all big and clever!! I've never posted 'help' before. I don't know what a Morris Minor engine looks like, but..... When our old BMW 3-series engine was overheating it was the thermostat that had jammed, either open or closed, I dunno which would make it overheat?? What you can do to test if it of the same type as ours was is to put it in boiling water, and see if it opens. I seem to remember you can live without the thermostat in the summer, but not the winter. I dunno, try taking the thermostat out and taking it for a spin, see if it still over-heats!!

- James xx 'much love'

Please tell me what you think of this post, tell me everyone if it makes any sense!

Post by **67trav** » Sun Jul 06, 2003 10:03 pm

Well done James. You are right; a jammed shut thermostat could be a potential cause (ie no circulation in the cooling system, therefore a rapid build up of engine heat unable to be cooled). I too experienced this in....a 3 series BMW!!
cheers. I'll post you elsewhere re: your search for a minor
Ben

Post by **Shmickle** » Sun Jul 06, 2003 10:15 pm

I'll post you elsewhere re: your search for a minor
Ben

I don't quite understand what you mean? But! thanx for the vote of confidence!!

Post by **67trav** » Sun Jul 06, 2003 11:10 pm

well it is like the cooling system has a given capacity of coolant (say 8 litres) to circulate around the engine- driven by the water pump, through the thermostat, the radiator and hoses.
If the thermostat stays closed the flow is effectively stopped (the flow is blocked off by the shut thermostat). This is a reason for having a thermostat, so that there is quite a quick warm up time when the engine is started (the engine generates heat by it running, but if it cannot flow and circulate the coolant around it rapidly heats up). A thermostat that is working correctly will open at a given (normal working) temperature (say 82C) and allow the flow to complete the circuit of the engine AND cooling system (radiator, etc). This means that the coolant will be heated by the engine (as a means to transfer heat away from the engine to stop it overheating) and flow through the radiator where the heat is disipated through the cooling fins to the atmosphere. The somewhat cooled coolant continues its cycle again through the engine, etc, etc. So the thermostat kind of acts as a regulator to flow of the cooling system at different temperatures.
Is that any clearer? (don't worry if it is difficult to follow- explaining things has never been my strong point!)

Post by **Shmickle** » Sun Jul 06, 2003 11:26 pm

No, I got that! I meant the bit I quoted,

I'll post you elsewhere re: your search for a minor
Ben

I didn't understand what you meant by the bi I have quoted above?

- James

Post by **67trav** » Mon Jul 07, 2003 8:04 am

Ah, sorry. A reply to your question 'what to look out for' (General Discussion)

Post by **Shmickle** » Mon Jul 07, 2003 7:00 pm

I get you know! Yeah, its a good thing to know about! I'm a natural!!!

Post by **ColinP** » Wed Jul 09, 2003 9:04 am

Dennis,

I've just fitted a new water pump and found it leaked between the block and the flange.

The blind hole in the pump body was not deep enough for the locating pin, leaving a 2mm gap for the gasket/sealant to fill - or not.

This only appeared as a slow drip on standing/idling, probably more when being driven.

Regards,

Colin

Post by **dennis** » Thu Jul 10, 2003 8:02 pm

hi all
problem fixed dodgy thermostat

Post by **Shmickle** » Thu Jul 10, 2003 9:44 pm

Do a little dance, make a little love, GET DOWN TONIGHT!!

Sorry everyone, that was my suggestion! and I don't know anything!