Vauxhall Astra - problems starting from cold - new radiator

It could be the coolant temperature sender, one of the cheap OMDII readers should let you find out easily.

Cold start valve possibly. Lack of servicing is another.

Two possibilities here:

a) immobilizer fault- do you get any flashing warning lights whilst attempting to start? You may have a faulty pick up coil or its connection around the ignition barrel.- basically the ecu isnt seeing the key, so the immobilizer stays active.

b) Coolant temperature sensor fault- so the ECU sets a fuelling level of about 70deg c rather than what it actually needs. Usually cold idle speed will be slow, prone to stall, and the engine will hesitate and splutter until it warms though about- as if it hasnt enough 'choke'.

Get a reputable locally recommended garage to have a look at it.

Tim..

Many thanks for the replies. I've taken the car into a locally reputable garage who have done a service on the car. There are no flashing lights when trying to start but Tim's summing up of "as if it hasn't enough choke" seems spot on to me. They've checked the coolant temperature sensor and have said that's sending out the correct readings. They've suggested changing the fuel filter as the next step. Anyone any thoughts? Is that a logical thing to try next?

Regards Helen

Regards Helen

Only if the fuel pressure's low.

Thus spake snipped-for-privacy@yahoo.com ( snipped-for-privacy@yahoo.com) unto the assembled multitudes:

I wouldn't have thought a choke comes into it at all, as a 2003 Astra will surely be fuel-injected and (AFAIK) doesn't have a choke as such. Has the service not cured the problem?

multitudes:

Hello No, unfortunately, the service hasn't helped at all

Regards Helen

Isn't the fuel filter a service item? I'd have thought a full service included a new one and it's not going to do any harm to replace it. To be honest I'd have expected problems when accelerating hard to show up before it was blocked enough to give a starting problem.

Does it have an air temperature sensor in the inlet track somewhere? If that's faulty it could think it's summer and not give it enough fuel. Also there are usually two coolant temperature sensors, one for the dash gauge and one for the engine management system, I presume they checked the correct one.

How does it run once you get it warmed up?

Many thanks for the replies. I've taken the car into a locally reputable garage who have done a service on the car. There are no flashing lights when trying to start but Tim's summing up of "as if it hasn't enough choke" seems spot on to me. They've checked the coolant temperature sensor and have said that's sending out the correct readings. They've suggested changing the fuel filter as the next step. Anyone any thoughts? Is that a logical thing to try next?

By all means change the fuel filter (when was it last changed- should be done at approx 40k intervals) but i doubt it will help. Even at cold start fuel requirements are low compared to say full throttle at 4000rpm so a partially blocked filter will usually show up as lack of power on demand.

Also check that the fuel pump is working- at key-on you should be able to hear it prime for a second or so, try it afew times. A lazy pump will give your symptoms also. Fuel pump relays are often the cause, although they usually die when hot- the parts inside expand and the pump then stops til the relay cools.

The next stage would be hooking the car upto a diagnostic computer with it cold and looking at the live data both before attempting to start, during, and immediately after. Ask your local garage if they can do this.

This will show any strange (plainly wrong) sensor values the ECU is seeing. It can only give the right settings if the info it receives is right.

Hope that all makes sense.

Tim.

That's really the only sensible option. The alternative is to change parts until it works and that will get more expensive than hooking up to a Vauxhall Tech2.

Hello all

Many thanks for all your comments. It seems the garage is 100% certain there's nothing wrong with the sensors and have informed me that due to the radiator over heating the cylinder head gasket has gone. I'm not 100% sure I understand what that means but I do know it means =A3=A3=A3= =A3 =A3

Regards Helen

If the radiators got exhaust gas in it then it's the head gasket.

The gasket failure allows water into one or more cylinders, this has to get blown out before it will start. A ballpark figure to fix it is about 500 quid.

Hello all

Many thanks for all your comments. It seems the garage is 100% certain there's nothing wrong with the sensors and have informed me that due to the radiator over heating the cylinder head gasket has gone. I'm not 100% sure I understand what that means but I do know it means ££££ £

Is it using coolant then?

Tim..

Yes - I think they told me water's getting into the cylinder head Regards Helen