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Overheating danger ?
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Tjensen   
Sat Sep 30 2017, 05:18am
Joined: Jul 17 2012
Member No: #954
Location: Bergen
 After two small disasters where the aux belt has come off, I wonder if I may have risked serious overheating :

1. Alternator freewheel crash: I did not know that water pump stopped together with steering pump and alternator, so I drove home with care, wathching battery condition.(20 km ?) after charging fault warning. Also got a warning about ECU losing power, but had turned screen off for most of the time to save energy. Full repair and driving 2000 km after this without problems.

2. Faulty fastening of the bolt that keep the aux belt tensioner in place and a new disaster like the previous one, causd by bolt working loose and breaking. This time I watched temperatures and only drove a few km's. Water temperature way up in the red and a overheating stop warning just before stopping. Oil temperature never got near the danger zone. Car now waiting for new bolt/belt/tensioner and timing cover.

No coolant leakage, but small amount coming out of the expansion tank .

Is there a danger of overheating damage and what will be the symptoms ?
e3steve   
Sat Sep 30 2017, 09:52am
Joined: Jan 21 2013
Member No: #1163
Location: Warsash, Hants & Palma de Mallorca, Spain
Tjensen wrote ...

After to small disasters where the aux belt has come off, I wonder if I may have risked serious overheating :

1. Alternator freewheel crash: I did not know that water pump stopped together with steering pump and alternator, so I drove home with care, whatching battery condition.(20 km ?) after charging fault warning. Also got a warning about ECU losing power, but had turned screen off for most of the time to save energy. Full repair and driving 2000 km after this without problems.

2. Faulty fastening of the bolt that keep the aux belt tensioner in place and a new disaster like the previous one. This time I watched temperatures and only drove a few km's. Water temperature way up in the red and a overheating stop warning just before stopping. Oil temperature never got near the danger zone. Car now waiting for new bolt/belt/tensioner and timing cover.

No coolant leakage, but small amount coming out of the expansion tank .

Is there a danger of overheating damage and what will be the symptoms ?


It's time to have the cooling system pressure tested, I'd say! First, run the engine with the coolant de-gassing tank cap loose, tighten the cap for a minute or so then undo the cap and see if there's a high level of pressure build-up; that could indicate a head gasket problem, whereby cylinder pressure is escaping into the cooling system...
Tjensen   
Sat Sep 30 2017, 10:13am
Joined: Jul 17 2012
Member No: #954
Location: Bergen
 Thanks ! Will do that. Should I also ask the garage that is doing the repair work to do this test ?

(Had this problem with my first car ,a Renault R4 1966. Never solved it properly, but changed head-gasket myself each year for some years. Will not try this strategy on the C6)
Cisco   
Sat Sep 30 2017, 04:46pm
Joined: Sep 10 2013
Member No: #1429
Location: Glasgow
 Hi again Tjensen,

Main worry will be a warped head/failed head gasket.

If your cooling system is being pressurized by the combustion gasses the gasket will have failed across the fire ring. There won't be much doubt.... the pressure will continue to increase until the coolant escapes from the pressure cap on the coolant bottle or a hose splits.

Other tell tale signs could be steam from the exhaust; oil in the water/water in the oil causing a white emulsion visible on the inside of the oil filler cap and/or scum in the coolant bottle.

Your garage will also be able to do a sniffer test on the coolant but to be honest if one or two of the gaskets have failed you will know all about it pretty quickly.

Disappointing that your garage messed up the installation of the aux belt tensioner. It is not a complicated install and the torque values are stated in the manual. I'm guessing they forgot to tighten one of the bolts. If so that's unforgivable.

Fingers crossed that it is all ok but coolant leaking from the pressure cap is a worry. Good luck with it.

p.s. Back in the day I worked on a couple of R4 engines. On the first one I took apart ALL the pushrods were bent. So much so that I thought they were meant to be that way until I checked the replacements
Tjensen   
Sat Sep 30 2017, 07:57pm
Joined: Jul 17 2012
Member No: #954
Location: Bergen
 Thanks for detailed and understandable advice. Cross my fingers......


My theory is that the R4 engine had "wet liners" that worked themselves down in the block, enough to make the gasket leak after some months. New gasket: Ok for a while. As an early car with degassing tank (of glass)the problems showed up there.
Tjensen   
Mon Oct 09 2017, 02:10pm
Joined: Jul 17 2012
Member No: #954
Location: Bergen
 Update: 500 km yesterday. Smooth Nice driving over autumn mountains. No indication of gasket failure. Hopefully this means that all is well. Fuel consumption a little bit higher that usual: 0,66 l/10 km instead of the usual 0,58. But there are at least 9 new bearings and new gear oil, so maybe a natural process. Thanks for good advice.
Cisco   
Tue Oct 10 2017, 08:00am
Joined: Sep 10 2013
Member No: #1429
Location: Glasgow
 That's great news. well done
 

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