overheating

Post by **Dru** » Mon Oct 13, 2008 5:45 am

On the positive side, the Trav's newly-installed head is ticking along nicely, and it now has a couple of hundred miles to its credit

But. The engine is still getting hot. The gauge indicates a temp of about 85 when tooling along at 60 MPH on the motorway, although with the warm weather yesterday it got up to 90+ even with the heater on full blast (and very hot and uncomfortable it was too). And when I checked the rad, I found that it had been discharging coolant through the vent pipe.

I've already done a two-stage flush through the system, and installed a new thermostat, and looked at the water pump, which looked just fine.

So I am guessing that maybe the radiator needs changing? -Can't think of anything else to do...

...and thinking of that rebuild, I had vaguely hoped that the BOKBOKBOK noise that the exhaust makes on deceleration would return after the rebuild. But it's not been there since the garage put a different exhaust on for me, last year.

Shouldn't all Morris exhausts go BOKBOKBOK? How can you tell if there's something wrong with the exhaust?

Questions, questions

Post by **DAVIDMCCULLOUGH** » Mon Oct 13, 2008 11:23 am

Before getting a new rad, try putting some washing powder in and taking it for a run then re flush the system. This can help shift any oily deposits left if oil got into the rad when the head went. Make sure it is well flushed out again, best way is to take it out of the car and flush both ways and also do the engine separetly. If it doesnt work nothing lost, then get a new one!!!

Post by **Dru** » Mon Oct 13, 2008 12:28 pm

Thanks for the suggestion, David; but while the head was off, I sat the radiator in the bathroom for a couple of days with acid descaler in it, then gave it a good flushing, and I fear that if that didn't fix it then nothing will.

Thinking new rads, I've been looking at a couple of online spares people, and one of them is offering "superior double core" radiators. Worth the added expense, I wonder?

Post by **Luxobarge** » Mon Oct 13, 2008 1:08 pm

Not for one moment wishing to cast nasturtiums on your head gasket, but was it overheating before you replaced this? Even if the engine itself appears to be running OK, it might be worth doing a compression test.....?

Gasket on wrong way. or blocked waterway? No offence intended, just a thought.....

Might not be the gasket itself, might be a crack? I do hope not....

Apart from that, according to your description, it sounds like it's overheating at speed but not when ticking over or at low speed? If so, these are the classic symptoms of a blocked radiator, so as above, replace it, or you could have it re-cored. Unless your engine has been tuned/modified quite a lot I'd have thought that a standard rad would be more than adequate?

If, however, it tends to overheat even when stationary/at very low speed, then this is rarely caused by the radiator, so you need to look elsewhere, although I concede you've already done all the obvious things!

When you checked the water pump, you did make sure the impeller was NOT loose on the shaft, didn't you? This would cause the problem...

Just a few random thoughts - hope this helps!

Cheers

Post by **Dru** » Mon Oct 13, 2008 1:36 pm

Much appreciated, Luxobarge.

I think the head gasket is a nasturtium-free zone...

It was overheating before I took the head off; the head that came off did have a crack in it, which is why I put on a replacement. I am very sure that the gasket is the right way round; and the impellor seemed solid. And the internal heater heats up practically instantaneously when switched on, so I am guessing that the flow is good.

And it is at speed that the problem occurs, so you have confirmed my fears that the radiator should be replaced.

Further to add some heat to the sauce, as it were, I've just come in from tinkering because there's a nasty squeal which sounds like a fan belt, but doesn't appear to be; not there in neutral, however I gun the throttle, but under load especially when pulling away; at constant speed, sound disappears. Lordy.... maybe should start yet another new thread...

Post by **Luxobarge** » Mon Oct 13, 2008 2:11 pm

Dru wrote:Much appreciated, Luxobarge. It was overheating before I took the head off; the head that came off did have a crack in it, which is why I put on a replacement. I am very sure that the gasket is the right way round; and the impellor seemed solid. And the internal heater heats up practically instantaneously when switched on, so I am guessing that the flow is good.

And it is at speed that the problem occurs, so you have confirmed my fears that the radiator should be replaced.

OK, that's useful information. Yep - sounds like new rad time! As I said, these are absolutely classic symptoms of a blocked rad, i.e. overheating at speed but not stationary.

Nice one - let us know how it goes!

Cheers

Post by **bmcecosse** » Mon Oct 13, 2008 4:26 pm

Well - winter is coming - so I would stick with that rad for now. maybe try fklushing the whole system through with drain cleaner - and if water has been coming out of the rad top then a new cap may be in order. Good idea also to catch the overflow in a plastic bottle - when the engine cools it sucks the water back in. It may simply be an over-reading temperature gauge -so unless you do find it's actually boiling i wouldn't worry too much. Certainly no need for 'double core' etc - Minor rad is excessively large as standard. Squeel WILL be the fan belt - so arm yourself with a new one and fit it when you get the chance. Tightening the old one will likely cause it to snap sometime soon. I suppose there's no chance it's got the wrong fan fitted - blowing against the rad instead of sucking through ?

Post by **MarkyB** » Mon Oct 13, 2008 6:40 pm

Good point about the fan.
The heater working so fast suggests that the flow may only be through the heater.
Squealing fan belt is often caused by the generator working hard to recharge the battery from the drain of starting the engine + lights, radio, heated rear window etc.
Worst thing you can do if its squealing is rev the engine up. High speed means less friction which is what the fan belt needs to do its job.

Post by **Dru** » Tue Oct 14, 2008 6:40 am

Well, I bit the bullet and bought a new radiator. I really want to sort out the niggles on this car; we do a lot of miles together, and I worry excessively if anything is not as it should be.

So I took it out for a test last night, and... lovely so far. The temperature gauge went sloooowly up to 80, then swung sedately down to 70ish, then back up, and so it continued to seesaw softly up and down as I bimbled around Bristol. Better than the telly, it was

The fan belt prob is fixed too; I went over to Charles Ware's for the new rad, as they're close by and convenient, and had a chat with Tim and Andy while I was there. Tim suggested squirting some WD40 on the fan belt (it's a new one I'd fitted while rebuilding) to help it settle in. Which seemed counter-intuitive to me, but heck, I've tried adjusting the tension several times with little joy.

*squirt squirt*

sorted.

....now, to look at the annoying rattle that's been developing from the area of the front wheel, before something falls off.

Never ending, isn't it?

Post by **bmcecosse** » Tue Oct 14, 2008 7:28 am

Welldone with the new rad - glad that's sorted although you may wish for that super heater in months to come. WD40 on the belt - well I never! It could still be slipping, bery possibly worse than ever - but the WD40 is now lubricating it and so you don't hear the squealling! Make sure you have a spare with you in the car - even an old one will do in an emergency.

Post by **Dru** » Tue Oct 14, 2008 8:59 am

It does seem perverse to improve the cooling just as we start to expect the first frosts, but I really wanted to nail this problem. Can't be any worse than the Austin 1300 I had yonks ago, where the heater didn't work at all. I remember driving along the M4 in freezing fog, draped in coats and blankets and losing sensation in my hands and feet....

Again, thanks for your input, all who have commented. I am getting to know my Trav better all the time. For better or worse

Post by **bmcecosse** » Tue Oct 14, 2008 9:40 pm

Seriously - worry about that WD40 'treatment' on the fan belt and make sure you have a spare handy!

Post by **Dru** » Wed Oct 15, 2008 1:48 pm

I shall, though it seems to have worked. The old one is in fair condition, and has joined the mound of odds-and-sods in the back of the car that may-just-be-useful-one-day

...found the source of the rattle, anyway; it was the front wing being a bit loose at the base. Temporarily fixed with duct tape, pending more serious fixing. What a relief. Just for now, everytihng seems tickety-boo

Post by **IslipMinor** » Wed Oct 15, 2008 5:56 pm

Dru,

What fan do you have fitted?

Post by **callyspoy** » Wed Oct 15, 2008 11:15 pm

what is standard running temperature on a mog then? say in normal moving traffic at 30ish, and also on a motorway doing 60ish.

Post by **alex_holden** » Wed Oct 15, 2008 11:21 pm

It should be somewhere close to the temperature of your thermostat. If it stays well below that temperature or it goes well over it then there is probably something wrong with the cooling system.

Post by **10852sm** » Thu Oct 16, 2008 2:59 am

On the same topic, how hot does your bottom radiator hose get after a run?

Mine is only just warm to the touch after a 30 mile run of about 20 miles of 65 mph on dual carraige way then about 10 miles at about 50 mph on A roads, with the heater on, at about 20 degrees ambient temperature.

The heater gets hot, the radiator gets hot apart from the bottom nearside where the pipe exits so I think the stat is opening and water is flowing through the radiator.

I have flushed the whole system and the radiator flows freely when fed with a hose, backwards and forwards, and through the drain, the top hose and the bottom hose connections. It has a 4 blade metal fan.

The car is a standard 1958 948cc, it has no temp gauge. Is it just a case of over cooling because it is a small engine and big radiator or do you think there is a problem? It shows no signs of over heating.

Thanks

Steve

Post by **10852sm** » Thu Oct 16, 2008 3:02 am

On the same topic, how hot does your bottom radiator hose get after a run?

Mine is only just warm to the touch after a 30 mile run of about 20 miles of 65 mph on dual carraige way then about 10 miles at about 50 mph on A roads, with the heater on, at about 20 degrees ambient temperature.

The heater gets hot, the radiator gets hot apart from the bottom nearside where the pipe exits so I think the stat is opening and water is flowing through the radiator.

I have flushed the whole system and the radiator flows freely when fed with a hose, backwards and forwards, and through the drain, the top hose and the bottom hose connections. It has a 4 blade metal fan.

The car is a standard 1958 948cc, it has no temp gauge. Is it just a case of over cooling because it is a small engine and big radiator or do you think there is a problem? It shows no signs of over heating.

Thanks

Steve

Post by **alex_holden** » Thu Oct 16, 2008 8:39 am

That sounds healthy to me. You want the water coming out of the bottom of the radiator to be cool. The thermostat should regulate the flow rate so the engine stays at about the right temperature.

Post by **bmcecosse** » Thu Oct 16, 2008 9:03 am

Normal on a Minor is a single 2 blade fan - sounds like you have 2 of these fans mounted at right angles. I would remove one of them - certainly in winter. The bottom hose being cool is fine - the radiator is doing it's job! The thermostat will shuttle between open and closed, modualting as it goes thus sending water through the rad only when required. Your 'double' fan is if anything over cooling the water and using up power and fuel!