Chaps,
I'm getting a little worried about the Mondeo's cooling system which is dropping some hints recently that all is not well. It has the following symptoms:
1) Slight coolant loss. As in MAX to MIN on the expansion tank every 2,500-3,000 miles or so.
2) Whiffs of hot coolant particularly at the end of a long run when parking up, and when first getting out of the car. This seems to be coming from the expansion tank area under the bonnet.
3) Temperature gauge climbs from its normal half way point to the 3/4 mark under hard acceleration, or VERY quickly in stop/start traffic. It doesn't go into the red and does drop back once settled in a cruise again. Ever since I've owned this car the gauge has remained stable, only climbing in Summer in really heavy traffic. The climbing under load is new. The rad fans seem to be working correctly.
4) Don't know if this is relevant, but I can remove the expansion tank cap with the engine hot and there's not so much as a hiss - like the cooling system is not pressurising. The cap was replaced about a year ago, as I had the odd coolant whiff (but not the other symptoms) and the "no pressure" phenomenon when opening the cap.
The engine is running perfectly (or seems to be), starts on the key from cold, and has negligible oil consumption. The coolant itself is translucent red with no crud or oily deposits in the expansion tank. There are no puddles under the car or steam escaping anywhere to indicate a leak. There is also no sign of mayonnaise inside the oil filler or on the dipstick.
The water pump was replaced 20,000 miles ago when I did the timing belts, and the thermostat is a recent replacement (Genuine Ford item) which I did when this started happening. It's made no difference. For what it's worth there is a healthy looking flow of coolant from the return hose on the top of the expansion tank which gets stronger with revs.
Any suggestions gratefully received. I don't want to cook the engine or get stranded and would rather nip any problem in the bud now. The car has done 141,000 miles and has always been superbly reliable.
Cheers as always!
DP
Edited by DP on 12/02/2008 at 22:00
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DP
Must be the cap again? There should be a little under a bar in there when hot; what do the hoses feel like?
Pumping it up to pressure and checking it's holding ability is the first test - or just try another cap.
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Thanks Screwloose. I'll try another cap first as it's an easy / cheap test. If not I'll get a pressure test done.
All hoses I can get to feel hot and seem to be in good nick. The rad seems to be getting hot, but access to it is tight with the twin fans and limited access from the front.
I'll have a proper look this weekend.
Cheers
DP
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DP
Sorry; it was the hoses squeezability that I was enquiring after, to determine if there was any system pressure.
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Screwloose,
The squeezability feels much the same whether hot or cold.
Cheers
DP
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Don't forget the rad itself can get silted up you need a pressure and flow test .
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10/10 to DP for an informative opening post.
I agree, try a new cap, wouldn't have thought the rad is silted if the coolant is clear and clean.
Good luck.
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The veins get blocket up over the years due lime scale and general crud the colour of the coolant will not change. There is a massive market in replacement rads judging by the amounts coming out of Marstons factory in Shipley.
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I had a coolant whiff with my old Mk1 Mondeo which was actually a very slight radiator leak which dried as it leaked so was only visible as a green stain.
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Thanks all for the replies.
I had chance to examine the car in a few minutes of daylight after I got home tonight. This is what I found:
1) There is DEFINITELY no pressure in the cooling system. I unscrewed the cap with the engine hot enough for the fan to be running. No hiss, no change in coolant level. I think I found out why......
2) Expansion tank cap "stops" against two plastic lugs on the bottom of the filler neck long before the rubber seal engages with the rim of the filler neck. The cap therefore cannot be sealing. This is a plastic threaded type cap with a black plastic valve of some sort on the underside in the middle, rather than the traditional metal one with the spring centre. It seems either I have the wrong cap, or the wrong expansion tank (?). I'm thinking the latter because the last cap had the same problem, and this one was definitely the correct one listed for the car.
Part of me feels like shaving a mill or so off these lugs with a Stanley knife to get the extra half turn or so needed to screw the cap fully home. I'm pondering this one for a bit before I jump in!
3) I managed to remove the plastic cover that goes between the grille and the scuttle panel (the one in the middle with the yellow air-con warning label). This gives good access to the upper half of the front of the radiator. I was surprised to find the radiator is stone cold, even with the temperature gauge at the 3/4 mark and the fan cutting in and out. The hoses either side of the rad are piping hot which suggests some coolant is circulating - it must be as the car is also not boiling over. But clearly coolant isn't flowing through the whole radiator.
So I'm thinking at the weekend I'll drop the rad out and flush it through, and either replace the cap, or make a small mod to the expansion tank. At least this will give a good chance to examine the external condition of the radiator, as between the various cowlings and the big twin fan assembly, it's somewhat buried in situ.
Any thoughts or advice welcome.
Cheers for all your help
DP
Edited by DP on 14/02/2008 at 18:51
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DP
I'd leave a settled rad well alone until you've sorted the pressure issue. You could be giving yourself unnecessary grief over nothing by causing it to start leaking.
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Thanks Screwloose. So are you thinking the lack of pressure could be causing the flow problem?
I'll be honest I don't think I've ever taken a rad out and found it to be in good enough nick to refit, so I'm not exactly cherishing the idea.
Cheers
DP>
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DP
Almost anything could be happening in an unpressurized system; so I'd take it one step at a time.
It's been a while since the system and rad was pressure-stressed; so that will be quite enough for it to cope with without re-positioning stresses as well.
If that causes a leak, then the decision regarding replacement is made for you.
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Thanks Screwloose. Your approach sounds like a much more logical way of approaching this. It had occurred to me that pressurising the system for what could be the first time in over 2 years might cause some new problems. I guess I'll just have to find out the hard way.
I think I'll try to get a seal with the cap I've got (worst case I'll end up having to replace the expansion tank in the longer term, but that's not the end of the world), and if that doesn't work I guess it's time to get a pressure test done to find out where the "leak" is.
I just hope it's not a head gasket or something more sinister.
I'll have a play on Saturday and let you know what happens.
Cheers
DP
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If it is completely unpressurised then the rad might not even fill properly hence the cold section.
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The radiator you are feeling is likely to be the aircon radiator which is in front of the engine one.
It could (note could) be a tiny head gasket leak.
Seems to me, from my experiences and that posted by others, the cooling system runs on a bit of a knife edge on Mondeos.
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The radiator you are feeling is likely to be the aircon radiator which is in front of the engine one.
OK. that's a little embarrassing. I think you could well be right!
I took a Stanley knife to the lugs on the expansion tank and this allowed the cap to screw down another half a turn and the rubber seal to properly engage.
Did my usual commute and the temperature gauge behaviour is improved. The highest it went was a needle's width over half way, and was much more stable overall. I got stuck in traffic for 30 mins and it didn't budge any higher, and dropped much quicker when I started moving. The coolant smell has also gone. But I still have no pressure in the system that I can notice when I undo the cap.
I think I'll get a pressure test done as soon as I can get it in.
I'll have a nose underneath tomorrow and confirm it is the air-con condenser that I've been mistaking for the rad! d'Oh!
Cheers
DP
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I only know about the radiator because I did the same thing!
Good luck.
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DP
Are the hoses firm when it's been running for a while - cap tight?
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Hi all,
OK, spent some time on/under the car this weekend (and discovered a blowing exhaust front section to add to the list, but that's another issue!)
I can confirm I was feeling the air-con condenser, not the rad. Oops! Rad is completely inaccessible in situ without removing the fans and shrouds, and to be honest I just don't want to disturb the rad at all unless I have to.
I changed the cap. The new one is shallower than the old one, with a shorter thread which would have seated without touching the two lugs although my Stanley knife mod means this wasn't an issue with the other one anyway. I'm still getting no pressure in the system, and the hoses can be squeezed just as easily when hot as when cold. Too early to tell what effect this has on the temperature gauge (if any). I suspect it will make no difference. I can also confirm that I checked every hose and connection possible and there is no sign whatsoever of coolant leaking externally.
I'm trying to get hold of a mate who can do the pressure test for me, but I'm starting to open up to the idea of a possible HGF. If this is the case, and along with the exhaust (quoted £205 as it has an integral cat!!!) and the front lower arm bushes and an intermittent clonk from the rear end which are going to need attention in the near term might make me start considering my options, and whether to punt it on with the faults for a few hundred quid and put the money, the repair costs (plus a top up) into something else. Not sure yet, but this car really does owe me nothing (£2k nearly 3 yrs ago, 46,000 miles covered, and virtually nothing spent outside of of servicing and tyres, and is starting to feel its age in a number of little ways - mostly small things, but they add up.
Thanks for all your help - I'll let you know what the outcome of the pressure test is.
Cheers
DP
Edited by DP on 17/02/2008 at 21:12
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DP
So you had the wrong cap on. Give it a day or two; I don't see the signs of HGF here.
The RF engine doesn't get very hot and may not pressurize quickly; provided that the gauge stays stable, then you may have cracked it.
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Well did my usual 35 mile run into the station this morning, monitoring the gauge closely. After the initial warm-up period, it settled just under the half way mark. After a couple of miles, it suddenly climbed to around 2/3 (prompting a sinking feeling and a couple of choice swear words), but immediately began to drop back again after just a few seconds. It settled at exactly half way (needle vertical), where it stayed for the remainder of the journey. Lots of traffic and the odd squirt up to motorway speeds from rest and it didn't budge.
Got to the other end at opened the bonnet. No coolant smell at all, even in that first "waft" of heat when the bonnet came up. I can still open the cap without it hissing though!
I am also quite certain that the heater feels hotter. It has always been excellent on this car, but this morning the air coming out of the vents was actually uncomfortably hot - I had the temperature dial turned off maximum despite -6°C outside.
To be honest, as long as the temperature gauge keeps behaving itself, I'm happy with that. I'll monitor the gauge and coolant level carefully over the coming days and keep you posted.
Cheers
DP
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Same again on the way home tonight. Settled at the half way point and fluctuated maybe a needle's width either side.
Quietly optimistic now.
Cheers
DP
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