Yes the Bosch + 4's can be used with Discovery II's. But they are finicky. On some rovers they work great, but others not so much. Go with the Champions OEM copper for testing then move to the Bosch + 4's or NGK iridiums once you have a good running idle with no issues for over 100 miles or so.
Buying spark plugs at the dealer is highway robbery! Once they replaced 3 of mine for $16 each...of course I never approved that. That was before I knew beans from shinola

 

I'm also getting the coil pack but not sure if its missing something there>>> http://www.roverparts.com/Parts/ERR6566.cfm .
part number> ERR6566 .

 

Are these the plugs i need??

http://www.partsgeek.com/gbproducts/...ek+Google+Base

 

Those Champion plugs look correct. I had those in my car originally when I changed them out at 65k. Those are good plugs, you may need to clean them and check them about every 25,000 miles. Even my E3 plugs get dirty! I shot them off with Simple Green and blow them off with the air compressor. This is mostly after an induction cleaning.

 

Just wanted to reply to this post. I drove the truck for about 1.5 yrs with the stat modded. The only problem i found was the truck didnt heat up properly. It would run really cold and the heat really didnt work. I never addressed this issue because i only drove it to work and didnt really bother me that the heat didnt work that great. I just recently had it overheat but i believe it was because i allowed the coolant level to get low from a small leak somewhere. I think it was at the throttle body housing. I just replaced the radiator and put an oem thermostat in it along with a new electric fan which i found wasnt working at all and was locked up. I believe it wasnt allowing much air thru the radiator. I drove the vehicle today about 30-40 miles with the stock thermostat in it and it seems fine but im still unsure about whether its fixed. I cant tell you that the mod works but i think some kind of an inline thermostat would be great in now allowing air to accumulate at the stat. I think the thermostat hogged out with an inline thermostat somewhere other than the stock position would make the truck run at normal operating temps without trapping air. Anyone have any ideas on some place to get an inline t stat? any info is appreciated. Thanks Kevin. I hope some of you did this mod and it worked. If not please reply i would like to hear what happened.

 

I ordered anew lower temp TS today, and am going to do your mod to my original stat tomorrow. If I had found this thread earlier I would have done the mod tonight.

I plan to do my HG next year. Great Basin Rovers did a dye and pressure test two months a go and reported very little HG leakage,so I Ho I can bide time.

I bought my 04 for $5k a few months ago. So far i have replaced 2 abs speed sensors need to mod my shuttle valve, powersteering pump is on the fritz. And now a cooling issue.

Blech!

I really hope these replacements/repairs can leave me with a relatively reliable vehicle.

My original plan was to build an overland traveler. Now I'm scared of this thing.

 

I think this mod will work for people with small headgasket issues. If your gonna hog the stat out I wouldn't go to the extent I did. Just put a bunch of big holes at every metal piece that looks like it could stop flow if an air pocket occurs. I took almost the whole inside out and it wouldn't hear up in the winter. I think a inline valve that I could adjust would work and still allow for heat. Like a valve for PVC pipe would work great. Just make sure u open the t valve on the upper radiator hose when filling the coolant tank. When it comes out the t valve let it set for about 15 seconds. I found it will lower a little if u let it set. That way your sure to get most of the air out. Then get it to operating temps and crack it open a couple times until u see coolant only squirting out.

 

"The way the system is set up i believe the coolant doesnt enter the radiator until the t stat opens it just runs in a closed loop from the waterpump to the heater core and when it opens this coolant is then directed to the radiator and back into the t connection at the top. If the t stat doesnt open then there is no way it can cool off. "

Ok, here is my two cents: The coolant will not enter or leave the radiator if t-stat is not open. In other words, the coolant is trapped in the radiator if the t-stat is closed. T-stat opens when hot water opens the spring, and this hot water is entering the t-stat from engine block on the way to water pump. If t-stat is closed it makes a loop w/o getting into the radiator. When the hot water from the angine activates the spring and opens the t-stat, water circulates through the radiator. So, the air cannot get stock in the t-stat if it operates properly! I mean, the spring pulls it up (not pushing from the bottom), and air cannot get stuck at the bottom of the t-stat. What you have done is just a common (but not a scientific) way of solving some over heating problems by putting your t-stat in always open form. It is ok to do it, even better in summer, but delays the heat in winters.

My suggestion is, when disco overheats, to check the hose connected to the bottom of the t-stat, coming from the radiator. If it is cold, but your disco overheats, change the t-stat, and buy an OEM one! I am serious, it is worth the money. After market t-stats are not good. I tried 3 of them. I replaced my radiator, and put a new after market t-stat, and my truck overheats! (2003 disco). I check the hose connecting the radiator to t-stat, and it is cold! (Brand new radiator, flashed cooling system, no air in the system, still overheats. Slight overheat, not the red light!) So, I drilled 2 very little holes (0.5 mm) in the aftermarket t-stat (a version of what you have done), problem solved. Better one is to buy an OEM t-stat. I will try this when I have time, and report here again. There is also a hot weather t-stat for Disco that opens earlier... Calll the dealer, or check Atlantic British. It is $47. Cheers! KT

 

Nope! Coolant enters the radiator from the driver side "up" entrance, and leaves it at the bottom exit of the radiator. T-stat is just there next to the exit of the radiator. So if t-stat is closed then coolant, air, and all other gasses are trapped in the radiator, if they ever enter there. Most of the time, this happens at the very beginning of the repair process. When you service the cooling system, (like I did, a new radiator, and t-stat), if you put the t-stat (and it will be in the closed position obviously) and try to fill the radiator, you will not succeed since the air is already trapped there, in the radiator! It will be very difficult to get this air out, if the t-stat is not functioning well.

What people do not realize that disco t-stat is letting the coolant out of the radiator! But t-stat spring pulls up the metal Flyin modified from the sides. What I do not understand with his fix is that if the t-stat functions properly, it uses the hot water getting in the top portion of the t-stat from the engine block and passes by the t-stat and goes to water pump...and makes a loop to the top entrance of the radiator....so if t-stat is closed, cooled water never mixes in it since it is not travelling through the radiator... So, I like the fix if the air trapped at the bottom of the t-stat causes an issue and the hot water entering the TOP section of the t-stat cannot open the t-stat. This is a bit questionable for me. I mean I do not see why air at the bottom part of the t-stat would affect the functionality of the spring at the top part of the t-stat? Will it make vacuum effect at the bottom part and would not let the t-stat open? I do not know! If t-stat functions properly, air will never get trapped in the radiator! But in my case, t-stat would not open, and I do not know why? I think, an OEM t-stat will release the air since it has this functionality... I used an after market, and drilled it with very little just to let the air not get trapped... after proper bleeding, now it works beautifully. I will try the OEM t-stat one day, it is only $43, while the aftermarket is $23. Not much difference. Cheers!