How To: Check & Change Glow Plugs

[Toe-blue]

Will be doing this job at the weekend. First time tinkering on this car. Have just taken advantage of renaults £60 service, which included diagnostics (i thought good deal). Renault wanted £126.50 to change these
Here's wishing me look...

[Liggy]

My car has been getting the Check Injection message, so that post should be useful. Although, I'm having another problem. The car seems to be consuming oil at a high rate. Like, since the start of March, I've had to refill the oil about 3-4 times. Would this be anything to do with the glow plugs at all, or would it be a different issue? I'm not very good with cars and mechanics, and stuff. Lol!

[craggle]

Great 'how to' guide. I stubbled across this when I Googled the 'check injection' fault and I'm now a member - great forum.

I did everything as explained and found glow plug 3 was dead. The code was still there even after disconnecting the battery for half hour. Had the fault code removed by a local mechanic. He found another 8 fault codes there but he removed the lot. All is ok now, except for the 35mpg average......next job on my small list of faults is to find why it's so thirsty.

Thanks for a great site.

Craggle.

[davet47]

This is an excellent post but on '06 and later 1.9dCi engines (the F9Q804 "euro 4) there is another plastic cover held down by two bolts-unfortunately some of the inlet pipework goes over this and 3 bolts and 1 nut need to be removed to allow this to be moved to one side for clearance. Once this cover is removed there is a"rail protector"(Renault Dealer parlance) which is a plastic thing that runs across the front of the cylinder head and for some reason obscures the RH end (no 4?) glow plug. I'm afraid when I got to this stage I couldn't see how to get this off and with it in place there is next to no clearance for the 10mm socket/extension-what it's for I've no idea!) so reluctantly booked it in to the local dealer, who was quite happy to use the glow plugs I supplied after I told them their service manager had confirmed the diagnosis of duff glow plug. Charged for 1 hour's labour which I thought was ok as it took me half an hour to reach the point of finding the plastic rail protector thing.
No I haven't got money to waste and I used to do all my own servicing on previous vehicles(which were admittedly older models and not Renaults) but vehicles are getting too complicated now .

[cyclonebri1]

That is a very detailed and well pictured post from the OP.

Unfortunately it's not the best way to test the glow plugs.

Simple, as in remove each one in turn, no pics needed and check the resistance, if you get a reading it is fine, open or closed circuit, then replace.

[davelowe]

I agree. Pull off the connector, and check resistance. Standard is around 0.6 Ohm. If infinite resistance or short circuit, its a dud. Remove it and double check with a spare battery. Should glow red hot in a second.

[Liggy]

I think this might be the problem I'm having. I had made a post called "Engine Light On." I was driving home earlier, and I noticed a lack of power in 1st gear when trying to start off. The Engine Light has turned off, but I got the Check Injection message. It put a shiver down my spine! Lol! Although, if it is the glow plugs, this post is going to save my bacon. Thanks for posting it.

[davelowe]

Mine starts fine on 3 glow plugs. I only found a problem after the 'check injection' message. If the glow plugs are fine, you might want to check out the regulator. They don't switch on and off like the olden days, the current is modulated during most non long term driving according to various sensors.

[polly59]

Had the check injection warning, changed number 3 glow plug. Now runs like a dream. So Easy!!!

[stevebetts]

Had the check injection warning, changed number 3 glow plug. Now runs like a dream. So Easy!!!

my duff plug was number 3 also.
Is it just me, or is this the one that everyone is reporting as going?

[LiamG]

Mine was number 3 too, read 0.00volts. My friend is a mechanic who said its a common problem on the 1.9 meganes and lagunas, always seems to be number 3.

Number 1 cylinder looks a pain to get out!

[sherbet0406]

Firstly can i say what a great post this is, a real money saver.

Secondly, does the glow plug control unit activate the glow plugs even when the engine is running( on warm up phase ). The reason i ask is that i have replaced two faulty glow plugs because the service and check injection light was illuminating when i try accelerating when the engine is warming up. The fault is still present so i am going to recheck the other plugs.
I have read on one of the posts about a regulator? What and where is this fitted?


Regards

Sherbet

[direstraits]

Secondly, does the glow plug control unit activate the glow plugs even when the engine is running( on warm up phase ). Sherbet

You're right, glow plugs operate until the engine is warm enough.

[davelowe]

What and where is this fitted?

On the 2002 - 2005 models it is fitted behind the near side front wheel arch cover (front section). It is housed in a plastic protective boot and looks like a lump of aluminium bolted to the bodywork with a connector on top. Disconnect the battery -ve lead before you remove / replace it.

[southleigh]

Had the Check Injection message and so got the diagnostics checked at an independent garage and was advised that it might cost a bomb to get rid of as no faults were showing. Just changed all 4 plugs without any hassle (once I'd got all the right tools) but managed to drop one of them so had to scrabble about under the car removing the skid pan so I could retrieve it! 'Check Injection' message now cleared!

Thanks for our advice!

Ben