1998 Discovery II
116,491 Miles

P0171 System to Lean - Bank 1

P0154 02 Sensor No activity

P0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
P0155 P0155 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
P0733 Gear 3 Ratio incorrect
P0734 Gear 4 Ratio incorrect

P1171 - Oxygen Sensor System too Lean Fault Banks A & B
P1300 - misfire ??

P0300 random/multiple cylinder misfire
P0301 cyl 1
P0302 cyl 2
P0303 cyl 3
P0304 cyl 4
P0305 cyl 5
P0306 cyl 6
P0307 cyl 7
P0308 cyl 8

Background story, the Land Rover belongs to a family member and they finally just want to get rid of it due to all the issues. It overheats after driving for 5 minutes (temp gauge slowly raises until red) and they are forced to pull over to let it cool off and they fill up the coolant with water (which is boiling at this point). They said they had the pump replaced a year or two ago and it fixed it for a while, then it started happening again. They also said they took it to a mechanic and they swapped sparkplugs/wires to try to fix the misfires but that didn't work.

It also has the three lights illuminated So I will probably have to do the ABS mod to fix that ( ABS Mod - LAND ROVER CLUB V.I. )

Would it be worth it to try to fix this Land Rover back to a good running condition? I have been searching some of these codes and it seems alot of them may be related to the MAF and 02 sensors... Even the Transmission codes may be related to the MAF? Could also be a bad vacuum hose that is causing alot of the sensors to act up?

I would appreciate any help or suggestions...

 

Job one is correct the overheating, otherwise the party is over and you need a whole engine. Here is one way to proceed:

Get a plug in scanner/code reader that can display live data, like coolant temp. Then you will know how hot it is getting, and once you pass 220 your can shut down, no need to go all the way to red line.

The number of times it has been run to the red line will increase the chances a head gasket is called for ($300 parts) and machine shop to skim heads back to flat ($200+).

The system is designed to show normal heat range from X to Y as 50% on gauge. Above 50% and you have begun over heat.

We will assume the following: water pump in good condition.

Things to check - belt route around the pulleys. Any time a pump is replaced belts can get back on wrong. See Discover Land Rover Discovery Serpentine Belt Routing Maintenance Tips

Fan function and blade direction - a paper towel should be held to the grille at idle, never blown away. Cupped sides of blade toward engine block.

Full of coolant and no gurgle sounds under dash. Air bubbles in coolant sound like water rushing under dash. Purge. If they return, can be exhaust gas in coolant, $50 chemical test at parts store for that, samples the water in the expansion jug.

New thermostat - they now sell a 82 degree C "soft spring" stat that allows truck to run 10F cooler. Your stat is remote, and has holes in the top to allow hot coolant to enter and mux with cooler liquid, and open the stat. If holes clogged stat opens late, if at all.

Radiator - many D2 used Dexcool which formed a sludge inside cooling system. Only in beginning stage can it be flushed out. Radiator is like $210. Test by warming up truck, cut off engine. Fins top to bottom should be close in temp, say 10F. Big spread indicated hot coolant at top, and very little flow at bottom (so it is mucho colder).

If you have coolant loss via oil pan, external gasket leak, or into combustion chamber - could be a head gasket. You can rent/borrow a coolant pressure tester, pump system up to 15-16 PSI and wait 30 minutes, leaks should appear. One owner had it leaking straight down out of the coolant jug from hose under it.

For it to overheat so quickly, either thermostat not opening, clogged radiator, or cracked block / head gasket. If overheating at 50 mph, fan clutch is usually not involved, becuase so much air flow from forward motion.

Pix of inside the stat and radiator. I would see if they will let you work on the overheating issue in their driveway before deciding to get the unit and tackle the rest. Can it be fixed? Yes. By a determined DIY? Yes, with some place to work that truck can be left out of service for a brief period of time (HG takes about two weekends with machine shop inbetween).

Pix of stat internal, rad sludge, and attachment of cooling layout.

 

Thanks so much... Unfortunately the vehicle is a few states away from me and it appears driving it to my location is not possible (due to overheating). I will make a list of troubleshooting steps for my family member to perform to try and narrow down the possible culprit. I'll have them start by seeing if the suction from the fan can keep a paper towel against the grill and removing the thermostat and seeing if it opens between 85-89* C (according to the D1 Workshop Manual)

One question though, "Full of coolant and no gurgle sounds under dash. Air bubbles in coolant sound like water rushing under dash. Purge. If they return, can be exhaust gas in coolant, $50 chemical test at parts store for that, samples the water in the expansion jug."

Are you saying that no gurgling sounds under the dash is good?

 

Yes, exhaust gas and air bubble sound the same. But - some owners have been known to bypass heater core lines, so that "test" is not valid. As for the stat, the shop manual says starts to open at 180F and full open at 204F. Many owners have installed with an after market modification that uses an in-line stat, or the "recently promoted" 82C stat, which runs 6 - 10 F cooler. My old D1 has a 180F $10 stat, and it runs 180 -183, until you get to 70, and it may get to 187. A D1 stat and D2 stat are different, and located in different spots.

But be warned, once you are stricken with Rover Rash, there is no known cure.

 

Hmm, I think I may have a Discovery I , not the Discovery II ... Thanks for your help though !! Greatly appreciated !

 

Hmm, I am having trouble finding pictures of the Discovery 1 Thermostat , the only guides, videos I can find are with the three valve discover 2 one...

 

Kinda confused about the year of your Discovery. Discovery series I ran from 1994-1999. Discovery series II rand from mid 1999-2004. If the hill descent and traction control icons are illuminated on your dash then you must have a Discovery Series II. Discovery I does not have hill descent control or traction control which means no 3 amigos. I think the first thing you meed to do is determine with certainly what the vehicle is in question: A D1 or a D2. If its a D2 and the 3 amigos are illuminated then you may have a lot of work ahead of you, if its a D1, I imagine you will have a lot less to worry about - not to say that the overheating isn't serious because it truly is. Either look at the registration or title, or upload some pics of the vehicle in question so we can better help you determine which vehicle you are dealing with. Use the resource below to help you determine which truck you have: https://landroverforums.com/forum/di...ry-i-ii-28599/

Good luck

 

Oh ok, I definitely have a discovery 2 then. Thanks for the link!!

 

I would be cautious as to how many times that engine has been overheated.

 

Before you do anything, decide what you have, there is no such thing as a 98 D2.
If you are looking to buy that truck, per your thread and all it's problems, stay away from it, it is a piece of junk.