Overheating, Misfiring - Need Opinions

[agro1]

I've been trying to diagnose a Check Engine code for a while now on my ?98 Rangie 4.0. I keep getting P1316 and P0304 ? misfire in cylinder #4. My coolant also seems to be going somewhere, and not on the ground in typical Rover fashion?
This all started happening about 5000 miles ago when I changed plugs. The #4 plug backed out and it threw the code ? tightened the plug back down, all good. It was fine for a while after that, but threw the same code again, of course. Mind you, I?ve been topping off the expansion tank with coolant every couple days or so. I?d say I?m loosing about 6-8 oz?s every 200 miles.
I?ve ruled out plugs, I changed to Magnacore wires and there are no coolant leaks anywhere. I need to get a better look at my coil pack, but initial inspection looks ok.
So on my way to work this morning, the CEL comes on followed by the temp gauge spiking into the red?Now I?m pissed. Pulled over, shut?er down and checked under the hood. Expansion tank is almost empty but the motor seems to be running fine and does not seem any hotter then normal.
Any suggestions guys ? Injectors, coils, valves (ugh ) ? One last thing. Cold startup. When I first start the car, it sometimes will idle rough ? especially if I put it in Reverse and keep my foot on the brake. Then after I run it through 1st and 2nd gear, it smoothes out?Could I have a head gasket leak into cylinder # 4 that is causing the coolant loss AND the Check Engine codes ? Thanks in advance for the help.

 

[p m]

It may be either head gasket or cracked cylinder liner. You may be able to find which one by doing a compression test - in my case with a 3.9, I couldn't see much difference.
After replacing the pass.side head gasket, I haven't lost a drop of coolant in a month.

 

[agro1]

Thanks Peter - guess it's time for a top end tear down...Lovely Man these Rover V8's really suck...

 

[Discodon]

blame Buick

 

[p m]

Discodon, I don't think it's Buick to blame here. Remember, they've only made the engine 215 ci big, not 242. Another classic example is old AMC 401 vs. 360 - neither is a champ, but the overbored ones live very short lives.
Also, it seems that aluminum engines really don't stand overheating.

 

[agro1]

Yeah - and Buick didn't make the heads nor the shitty gaskets that I'm sure don't have copper or stainless rings around the combustion chambers...I'm pretty convinced it's a head gasket failure considering the amount of coolant loss over the weekend.
How can I tell if I've damamged the internals of the motor ?? It only overheated for a min or so before I shut it down. I guess if it were really fucked it'd run like crap and make all kinds of nasty noises, right ??

It's amazing...The Rangie will chime and throw all kinds of friggn bells and whisltes until you put you seat belt on...God forbid it sound any type of warning buzzer when your temp guage hits RED...LAME is an understatement.

 

[p m]

I'd pull the heads first and take a look at the gaskets. Start with the one where OBD2 indicates the misfire. If the gasket is bad, check the head to make sure it isn't warped (and plane it if it is), before putting it back together. If the gasket and head are okay, you need to check the cylinder for a cracked liner - I have no opinion here besides UV fluorescent fluid and light.

Pulling the head isn't that difficult, it must be faster on the 4.0/4.6 than on 3.9 (fewer parts in your way). Now I think I could pull the intake/ram housing/plenum cover/fuel rail as an assembly, rather than taking it off piece by piece - but I'm not certain.

 

[agro1]

Yeah - you can. For the most part, the intake runners etc all come off together...It's not hard, just time consuming and tedious. With the help from RAVE, I'm sure it'll be fine. Now the cylinder part has me a bit worried...that would be bad news to have a cracked sleeve...
One other thing - I'll have a head job done while the heads are off. Clean up those valves etc...

 

[p m]

you may want to take the hood off. Pretty ugly to have to bend over the grille or the fender with intake/ram housing/plenum chamber in your outstretched hands, and have to manoever the shebang under the hood.

 

[agro1]

Good call man - then I can change the washer nozzles that are messed up...Thanks for the tips, Peter

 

[Steve83]

I agree that it's probably a head gasket leak into #4 - I see several each week, but most people don't want them fixed because of the cost. $16 for a head gasket, ~$2000 to put it on!

You don't have to remove a RR hood - just pop the gas struts loose, lean it straight up, and engage the locking clips. But I normally do them with the hood as-is.

The lower intake comes off with the fuel rail still attached, but the upper intake has to go first.

I have a BUNCH of the parts you'll be using; original LR, most still in the packaging.

 

[agro1]

Steve - Thanks for the reply man. You bring up an interesting point, however I'm getting some conflicting information...Now, I've been told that the misfire code in #4 CANNOT be a head gasket because there is NO WATER PASSAGE near cylinder #4 - therefore it HAS TO BE the cylinder/sleeve...
I'm not quite sure this makes any sense to me, considering I'm getting white smoke out the tailpipe - every indication would lead towards a head gasket.
A few questions:

1. Will a leakdown/compression test reveal WHERE the leak is, ie. block or head gasket ?

2. Does anyone have a picture of a LR head gasket showing cylinder #4 and the surrounding water passages ?

3. What's a good source for Rover motors (in Southern California) ?

Thanks again for the help guys.

 

[agro1]

Bump...

 

[p m]

Luke,

I'd suggest you swing by Behr's shop (Sport Utility Motorcar, off Miramar, 453 6234) - he has never been wrong in something like 5 years I've talked to him or had him do the job.
If there's something you don't like, Jim Newman's shop (Rover Group was the name, don't know if it's still the same) is a couple blocks away from Behr. Jim's got the Rovacom, a bit more advanced diagnostic tool.

I feel bad about picking his brain often - my excuse is that he's my only parts source.

 

[agro1]

Peter - Yeah, I know Jim and Jennifer, good people. I actually bought the Rangie from the guy that was running Premier Rover Sales next to them for a while - he's since closed doors and has gone back to work at Pioneer. Good guy, very knowledgable, guess it's just bad luck on my part that my motor is having trouble. I need to figure out if it's a just a head gasket or the block. Thanks for the tips nonetheless.
Does anyone know if you can pressure test the block without removing the heads ??

 

[p m]

yes, to some extent. You can use the adapter from compressed air hose to the spark plug, with the valve and gauge, pressurize it and notice how much time does it take for the pressure to fall. Compare different cylinders. Also, if the leak is into the coolant circuit, there will be bubbles in the expansion tank (keep the cap off). If you have a really good ear, you may distinguish between leaks into the block (rings), intake or exhaust (valves).

 

[Steve83]

...there is NO WATER PASSAGE near cylinder #4 ...

Right - I have FORD on the brain. LR (Buick, GM, etc) cylinders are numbered in odd & even banks, so the water journals are by 1,7, 2, & 8. The leaks I see are usually by #7 (4 if it was a Ford).

 

[agro1]

Thanks for the reply, Steve. Seems I'm lookin' at a new/rebuilt 4.6 . 'Preciate the help man

 

[antichrist]

Unlikely at this point, but how did you "rule out the plugs"? It's rare, but it could actually be a faulty plug. Many years ago I put brand new plugs in a Series, and swapped out the distributor at the same time. Wouldn't run worth a crap, so I figured I'd screwed up the distributor swap. I messed with it for waaaay too long. No luck. Out of frustration I tested the plugs. 2 of the 4 NEW plugs were bad.

 

[agro1]

Antichrist - 'Preciate the suggestion, but remember, I'm loosing LOTS of coolant, and it ain't going on the ground.

Well, I have a few options now since it's pretty clear the block needs to be replaced. However that brings up a few questions; LR blocks. Is there a difference between the GEMS block and the Bosh block ? I have been told the latter of the 2 is a "stronger block". I've also been told they are identical. Any comments about this ? It's my understanding that the only difference in the 2 motors is the top end (mostly intake) and the fuel management, right ?

I've spoken with a few people about getting short and long blocks, and am feeling a bit confused with what to do. Here are my current options:

1. Built motor (4.6). Machined, ported polished custom heads - bottom end totally reworked all new custom parts (Cloyes duplex timing set, OEM big rod and main bearings, RPI cams). Motor is very similar to an RPI motor - brand new. New intake, ported to match, and polished. Includes all gaskets and parts top to bottom - $3500 Sounds like a very nice, well built motor. Can the 4.6 block handle the added hp, though ?
2. Short block (4.0) with 200 miles on it, warrantied out by dealer with coolant leak. Bottom end is basically new and the block was welded to fix the leak. $1000
3. Boneyard long block (4.0). Pressure tested fine, unknown mileage. $1800
4. 4.0 short block. High mileage (100k+), but sounds ok. $750

Couple more questions and a final comment. Can you pressure test a short block ? And lastly; typically what fails on high mileage Rover motors ? The block or the internals ?
I could do alot of the work myself, but really don't have the time or tools to get it all done. So, I'm going to have to pay someone else to do the R&R on the motor and the rebuild. I know this is a long winded post/thread, but I'm really hoping someone can steer me in the right direction here. Thanks again guys,

Luke