Hey guys,
So yesterday after work I started up my disco and it was idling pretty rough and it threw a check engine light. I went to advanced auto and used their OBD scanner and it said there was a misfire with cylinder 7. Any advice to what I should be looking for, or checking out? I started with testing the fuses after make sure the spark plug was tight and the connection was secure (gotta start with the basics right?) , but that's all I had time to do so far. My brothers told me to check the spark plugs to see if they're fouled (which they probably are, my disco has ~235k miles, its still solid though) and then the wires. Just wanted some more input. Thanks!

 

Those are the same items I would check:
- HT leads... fully inserted onto spark plug and ignitor coil pack, check condition of leads for burns from laying on exhaust manifold. You can swap HT leads with cylinder 8 since they are the somewhat the same length to test out
- Spark plug... cracked ceramic, fouled/worn plug, too large of a spark gap. You can always swap out a good spark plug for the one on 7 and test out.

BTW... If cylinder #7 is giving you trouble and not cylinder #4, that tells me the coil pack is still good since 7 & 4 share the same single coil.

 

Are you losing any unexplained amounts of anti-freeze?

 

@The Deputy no not because of the misfire. I had a leak in the top rad hose where I'd have to fill up alotbut I got that fixed and it's not consuming any coolant... yet 😂

 

The amount will be minimal, if leaking internally into cylinder (at first) and may go unnoticed...especially...since you had another leak previously. Top it off and keep a good eye on level after several miles of driving time. You can also buy a tester that measure exhaust gasses in the coolant...or rent one...and this will take a lot of the guess work out of this (regarding head gasket).

But, if you are certain there is no issue with internal loss of anti-freeze. Justdo your basic diagnostics, looking over wiire and plug. Maybe swap a different wire into the equation. Also, running some injector cleaner through it won't hurt. Could be fuel related.

 

I would check compression too

 

Hi, I seem to be having this same issue (misfire cylinder #7, and losing anti-freeze; and when I check the spark plug (#7) I notice it being white vs the color of the others, ah and quite dense white smoke out the exhaust on start and stays for a while after driving it).

What could the issue be? and am I in for a huge expense on repairing it ? I have a Land Rover Discovery 2 from 2003 with barely 45k miles. Any guidance on how to approach this issue will be greatly appreciated.

 

Blown hg. Do a cooling system pressure test.

 

Thank you for your response! What would the pressure test show, that it is indeed a blown HG? Apols for all the basic questions but I am freaking out at the fact that this may set me back a good amount of $$$... I'm in Westchester NY and wonder if there is a LR independent mechanic that can perform this test...

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You can perform this test yourself, Advanced Auto Parts has a cooling system pressure test kit that you can rent/borrow. Start the test with the engine cold and off, pump it up to about 20 or 25 psi and it should hold pressure overnight. Once it is up to pressure if there are any external leaks you should be able to hear them or see them. If it does not hold pressure and there are no external leaks that means it is leaking internally. You can get a borescope off of Amazon for about $20 and check each cylinder through the spark plug hole to see if any coolant has leaked into the cylinder from the pressure test. Best to do the test with the spark plug out of cylinder 7 and 8 and then turn it over by just momentarily bumping the starter so that it moves very slowly and expels any coolant that has accumulated in the cylinder through the spark plug hole. People with major leaks have been connecting rods by filling the cylinder with coolant and then hitting the starter. Some of our Northeast contributors should be able to comment but to my knowledge Atlantic British, JE Robison, and TWS are not too far from you.