406oc.co.uk

Firstly HELLO again sorry for my Absence been busy the last few months I have been logging in but not posted.

Some of you may know back in August I had to scrap my old 406 so bought a C5.... Lovely car drives well (Shite mpg) It's still the 2.0 hdi 110 on an 04 plate.
Here's the problem.
Early November I had the coolant light come on so topped it up and ever since it's pressurising... Had a sniff test done before Christmas that was clear so tried a thermostat change (Bottom hose gets hot, top hose luke warm)... Only done short journeys after that up until Boxing day... Still pressurising up until then.

We had boooked a holiday for Dec 27th and paid for so we went... Lost about a coffee cup full of coolant on a 90 mile trip and probably about the same driving around for the week.... Drove home after New Year and lost about a litre of coolant

All this time I've noticed no leaks so yesterday a good friend of mine borrowed a coolant pressure tester and we gave it a try.. Everything holding fine with no leaks or escaping air... Mate suggested running it without the thermostat and sure enough it was stuck closed (Looks like it could be from the k-seal type stuff put in when they done the sniff test that I forgot to mention)

Running without the thermo in place I was kind of optimistic but the short 5 mile drive from his house saw it pressurised again with the new cap sounding like hissing Sid

Where now? Flush the whole lot out and start from scratch? Maybe the rad is blocked or one of the pipes?.... Thanks in advance lads.

Just noticed this very helpful video from Frank that I may try next...Not sure how much antifreeze should go it though any ideas?

https://www.youtube.com/watch?v=vssQVTSWLGo

My mate had the same sort of problem with a Range Rover and it turned out someone had put a shed load of K seal or similar in it for some reason or another and the cores of the rad were 70% blocked,we dissected the rad and you could see all the blockages,he fitted a new rad and it's been fine ever since.

grasmere59 wrote:My mate had the same sort of problem with a Range Rover and it turned out someone had put a shed load of K seal or similar in it for some reason or another and the cores of the rad were 70% blocked,we dissected the rad and you could see all the blockages,he fitted a new rad and it's been fine ever since.

I'm obviously no mechanic but the top hose being colder made me think the rad is full of crap.... Something's not flowing at the right flow rate methinks, thus creating air bubbles that need to get out?

It's usually quite simple to find if you have a blocked radiator....when up to full temperature feel all over the rad surface, any blocked area will show as cooler or cold in relation to the rest of it.

I assume you bled it properly after replacing the thermostat?

Nope he replaced the thermostat on the flat and yesterday when we removed it... It was to awkward to get the off side up in the air due to doing it alongside my mates garage with people driving past (badly) in the snow

I'm tempted to take the new stat that won't open back, grab some more antifreeze and follow Franks video for proper bleeding... Only downside to that is the weather.. If i go shooting water all over the car park next to my house and it freezes i'll errmm... Get in trouble with the neighbours

grasmere59 wrote:My mate had the same sort of problem with a Range Rover and it turned out someone had put a shed load of K seal or similar in it for some reason or another and the cores of the rad were 70% blocked,we dissected the rad and you could see all the blockages,he fitted a new rad and it's been fine ever since.

Once you read past the OP's comments about k-seal, and blaming it for this or that,
you'll see that he had the problem before the k-seal, and he had the problem after it.
So the problem is not the k-seal.

He's replaced the thermostat. So by deduction, it does look like the radiator is toast.

trufflehunt wrote:

grasmere59 wrote:My mate had the same sort of problem with a Range Rover and it turned out someone had put a shed load of K seal or similar in it for some reason or another and the cores of the rad were 70% blocked,we dissected the rad and you could see all the blockages,he fitted a new rad and it's been fine ever since.

Once you read past the OP's comments about k-seal, and blaming it for this or that,
you'll see that he had the problem before the k-seal, and he had the problem after it.
So the problem is not the k-seal.

He's replaced the thermostat. So by deduction, it does look like the radiator is toast.

This is how mechanics/garages get into trouble....never replace a part unless you are certain it needs replacing!
Never assume anything!

trufflehunt wrote:

grasmere59 wrote:My mate had the same sort of problem with a Range Rover and it turned out someone had put a shed load of K seal or similar in it for some reason or another and the cores of the rad were 70% blocked,we dissected the rad and you could see all the blockages,he fitted a new rad and it's been fine ever since.

Once you read past the OP's comments about k-seal, and blaming it for this or that,
you'll see that he had the problem before the k-seal, and he had the problem after it.
So the problem is not the k-seal.

He's replaced the thermostat. So by deduction, it does look like the radiator is toast.

I mentioned it might be because of the k-seal because there's a white gunk stuck to parts of the thermostat... We put it in a cup of boiling water and it didn't budge.

#Timetogetthematchesout.

jasper5 wrote: This is how mechanics/garages get into trouble....never replace a part unless you are certain it needs replacing!
Never assume anything!

That's the point of me trouble shooting it myself if I can, Just not even sure my thoughts of a coolant flush and proper bleed will be good enough or even worth the effort.

Sounds like the rad is partially blocked to me.

Welly wrote:Sounds like the rad is partially blocked to me.

It seems to be pointing towards that don't it... My lmf gave me a new thermostat today so i'll give it a good flush and top up when the weather permits.

Ah blx I changed the thermostat and flushed and bled it like in Franks video and it's still pressurising.... One thing I did notice it after an hour of getting it up to temp the radiator was hot and all the hoses except the top hose is this normal behaviour? the only way to get the top hose hot was to open the thermostat bleed valve and let some water out..

HELP Please..

Did you test the thermostat? I'm not sure it's the same any more but I used to buy loads of duff'uns.

steve_earwig wrote:Did you test the thermostat? I'm not sure it's the same any more but I used to buy loads of duff'uns.

Not before putting it in no... Wish i had now.