406oc.co.uk

Hi,started my 406 TDI 1999 saloon the other morning and the temperature rose very quickly I discovered that the engine was partially frozen.I pulled in till temperature dropped again,there was steam coming from from the header tank.It is now very hard to start at least 3 or 4 tries with turning over for a long time.The engine oil is not emulsified and there are no bubbles in the coolant.Good battery and engine turning over fast.It is running as normal when started and starts easily when warm.Any ideas of what I may have damaged or how to fix?

I take it you mean 'Hdi' they are a different kettle of fish to the XUD. The glow plugs have little effect so you are probably looking at low compression, possibly due to a cracked head or if its been used for a long period with no antifreeze could be that the head gasket has corroded. You need to get a compression test done.

Peter

What if the water pump froze?....start engine.....water pump impellor shears off...engine runs but no circulation so overheats? also possible that the cambelt has jumped a tooth in the process and therefore the crank/cam sensor can't see what's going on properly so poor starting.

Thanks for replies.The engine dosen't over heat now so I presume the water pump is working ok.If the head gasket was gone would there the oil not be emulsified or bubbles in the coolant tank.I checked the heater plugs by the test light method and also a clamp ammeter which is showing 25 amps before the heater plug relay turns off.Is there any way the heater plugs may still not be working?
"the cambelt has jumped a tooth in the process and therefore the crank/cam sensor can't see what's going on properly so poor starting"
How can I check this problem and fix it

Is it an Hdi common rail engine, look at the injectors, are they all connected to a thick pipe or is there an injection pump to which the pipes go? we need to identify which engine it is before we can offer an accurate diagnosis.

If the head gasket is leaking it will not necessarily leak oil into the water, depends where it has failed, same applies to the head. Does it tickover evenly?, do you get a lot of blue/white smoke when it starts?

Peter

Its a 1.9 turbo diesel engine.There is blue smoke for about 15 seconds when it starts.Its the same as this one.Peter would you convinced it is not the heater plugs from the tests I've done?

Very common to have the heater plugs go down on this engine!

To test the heater plugs without removing them...
Undo the main wire going to the plugs and remove each wire from the heater plugs...
Connect a test lamp to the battery live and touch each plug in turn with the other test lamp connection...a good plug will light the test lamp.
If the engine starts when warm it's unlikely the timing belt has slipped, but don't rule it out until the glow plugs have been checked....It's a big job to check it and you'll end up with a new belt and water pump anyway.

That is the way I tested them and all good.If the timing belt has slipped could this still be the reason for the hard starting when cold?Would the engine not be running differently because the belt has slipped?

Peter the engine does tick over evenly.

Dano41 wrote: ↑Tue Mar 06, 2018 1:16 pm That is the way I tested them and all good.If the timing belt has slipped could this still be the reason for the hard starting when cold?Would the engine not be running differently because the belt has slipped?

In theory, if the engine is running fine then the timing hasn't slipped.

Have you tried bypassing the glow plug relay?

No,I will try bypassing and see if any better.

Tried by passing the relay there was 25 amps been drawn on the cable it would not start.Would you rule out the heater plugs completely now?Put a heat gun on the block for 10 mins and started first turn.Slightest bit of blue smoke for a few seconds then clear.

Not sure if 25A represents all 4 glowplugs working OK, may be worth checking individually

I think I would be fitting a new set of glow plugs, even if it's just to eliminate them!

Ok folks thanks for sticking with me.Will replace plugs and report back.