| Author | Message | ||
     Chris Sears (Sears) New Member Username: Sears Post Number: 10 Registered: 02-2004 |
Folks, I just picked my 2000 Disco up at the dealer yesterday after having my 3rd head job/valve job in less than 2 years (the first was in Oct 2002, the second in Sept 2003, and the last one yeseterday). I am told that this time they replaced the valve guides with a new set from LR that have been tapered and are, in general, made to prevent the problems I have experienced in the past. The problem is the usual, sticking exhaust valves due to carbon build up and subsequent misfiring, thus lighting up my dash. My question is, should I beleive that this actually will be my last valve job for a long while or is my truck just a big POS in terms of this? They have replaced the head as well with a rebuilt head from LR. I haven't had to pay for any of these jobs yet, as the first was covered by my factory warranty at 45k, and the 2nd and 3rd covered themselves under the dealership's 1 year parts/labor warranty on all work. My truck now has 59k on it. My goal is to drive the truck forever but I surely can't afford valve jobs this often if I ever have to pay for them. Please advise. Thanks everyone! Chris | ||
| Dean Brown (Deanbrown3d) Senior Member Username: Deanbrown3d Post Number: 1661 Registered: 02-2002 |
At least once or twice a day you should floor the gas peddle and bring the revs up to 4-5K. You could use seafoam on a regular basis also, in your air intake, several people I know have said the stuff is remarkable. Also I'd use a relatively thin synthetic oil (5W30, Mobil 1) and keep that stuff splashing around the heads and rockers. D | ||
| Chris Sears (Sears) New Member Username: Sears Post Number: 11 Registered: 02-2004 |
Dean, revving the engine like that won't hurt it? Do you reccommend doing it at a standstill in neutral or while driving? Or does it matter? I have heard seafoam works well, I may try that after a few months. I am a bit scared to move to synthetic, as my disco has always had Mobil 10W-40 dino oil, and several people have had issues of one sort or another when changing to synthetic. My biggest problem may be driving her too easy. Thanks for the advice! | ||
| Peter J Blatt (Peteb) Senior Member Username: Peteb Post Number: 372 Registered: 10-2002 |
Running the engine up in revs while accelerating is a good thing, jack rabbit starts are not necessary, I run rotella oil, very high in zink (our friend) 4.0 108 k miles, Dont be afraid of flooring on occasion! Peter. | ||
| eric johnson (Eric2) Senior Member Username: Eric2 Post Number: 334 Registered: 05-2003 |
The polymers in multi-grade dino oils are what makes varnish and sludge. The higher your base number in a multi-grade,i.e., 20-50, the less polymers. The lower,i.e., 0-30 or 5-30, the more polymers there are. Synthetics are NOT made from the same base stock, and the polymer issue doesn't apply to synthetics. 10-30 or 20-50 Mobil-1 or better. Better being Royal Purple, Redline, Amsoil. | ||
| thom mathie (Muskyman) Senior Member Username: Muskyman Post Number: 676 Registered: 11-2002 |
just drive it like you stold it all the time and you will avoid carbon. these things are geared to cruise around at under 2000rpm...that alone is a sure fire way to carbon on the valves. | ||
| Wicks (Wicks) Member Username: Wicks Post Number: 176 Registered: 03-2003 |
Gosh, no. Rover V8s are so detuned you can't even make them work at full throttle for an hour. I drive my Defender around with a 100 lb weight on my foot. | ||
| Shaun Power (Shaunp) Senior Member Username: Shaunp Post Number: 282 Registered: 05-2003 |
Guys I don't understand why you guys in the US have so much trouble with this. While it is not unheard of in Australia it seems to be rare and the heads are more likly to come of due to head gasket failure after pretty high milage. What's different, is it fuel quality,fuel map, oil or what. I can't see how pooring carbon remover down the intake will solve an exhaust problem as the solvent would be burnt during combustion, it would clean inlets and chambers. I don't reckon much if any would get to exhausts during the overlap period. | ||
| Mike Rupp (Mike_rupp) Senior Member Username: Mike_rupp Post Number: 352 Registered: 02-2002 |
Chris, synthetic oil is fully compatible with regular oil. No reason to be scared. Make the change. They do a better job of keeping the engine clean. Eric, I'm not exactly sure what you're talking about. From what little I know about oil, the conventional oil has a much more broad molecular weight distribution than synthetic oil. What happens is the short chain oil molecules will burn off much easier contributing to the sludge problem. The synthetic oil has a tight molecular weight distribution, thus no small molecules to burn off. | ||
| Peter Matusov (Pmatusov) Senior Member Username: Pmatusov Post Number: 1458 Registered: 09-2002 |
Mike, I think Eric talks about thickening agents - if you start with a 0W-grade base, you need to add something to it so it doesn't turn into water at 200-250F. The lighter is the base oil, the larger is the amount of thickeners in oil. I have never thought about it, and never read about thickening agents burning out and causing carbon build-up problems. I don't think this is a significant effect, otherwise they wouldn't use 0W50 or 5W50 oils in high-performance cars (my logic may be wrong, though). Eric says this effect only appears in mineral-based oils - I don't see how synthetics are different in this respect. | ||
| Beau Campbell (Bcampbe7) New Member Username: Bcampbe7 Post Number: 40 Registered: 03-2004 |
Mike- I use sythetic, so I am not needing to switch, but in Chris' case will switching to synthetic from conventional oil cause leaks to appear? Beau | ||
| Chris Sears (Sears) New Member Username: Sears Post Number: 12 Registered: 02-2004 |
Beau, that is exactly my worry. I know that the two are compatible, e.g. I can switch to synthetic in a car that has always had dino, or vice versa, however I am a bit nervous, as now my Rover doesn't leak a drop (knock on wood) and I don't want to encourage it to. I change my oil very frequently (no more than 3000 miles) and have had other cars run off dino oil for over 175k with no (seriously none) engine work. A valve job in general is something I don't expect in any car I would pay more than 20K new for, much less a 35k+ disco. I don't really see the connection between synthetic oil and valve jobs. It seems to me to be more of a fuel quality/driving style/design flaw issue. Please explain your synthetic theories further. My car doesn't use/consume oil either. | ||
| Peter Matusov (Pmatusov) Senior Member Username: Pmatusov Post Number: 1461 Registered: 09-2002 |
Chris, I've gone from mineral to synthetic at about 100kmi, and 47kmi later still no leaks. | ||
| Steve Turpin (Steveturpin) Member Username: Steveturpin Post Number: 74 Registered: 01-2004 |
Chris, I just got done having to put a new short block in my 99 D2 along with it's second head rebuild/valve job...luckily much of it was covered under my extended warranty. I hope mine lasts as well, as I plan on keeping the truck for a long time...I'm at 72K now. I have always driven my truck hard in terms of revs and changed the oil every 3K... | ||
| Peter J. Kelly (Pjkbrit) Member Username: Pjkbrit Post Number: 88 Registered: 05-2003 |
American fuel quality is poor, they think 93 octane is premium...also they run these motors lean to meet emissions ... also leads to carbon build up...my 99D2 has 70K/runs synthetic/gets driven fairly hard and has been OK so far ... but it's a crap shoot and makes me nervous. My 85 Saab 900T has 275K with an untouched head...go figure! | ||
| eric johnson (Eric2) Senior Member Username: Eric2 Post Number: 337 Registered: 05-2003 |
Google is your friend - Now you can become knowledgable about Multi-Vis oil (sorta' long, but worth it) Multi viscosity oils work like this: Polymers are added to a light base (5W, 10W, 20W), which prevent the oil from thinning as much as it warms up. At cold temperatures the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot. Multi viscosity oils are one of the great improvements in oils, but they should be chosen wisely. Always use a multi grade with the narrowest span of viscosity that is appropriate for the temperatures you are going to encounter. In the winter base your decision on the lowest temperature you will encounter, in the summer, the highest temperature you expect. The polymers can shear and burn forming deposits that can cause ring sticking and other problems. 10W-40 and 5W-30 require a lot of polymers (synthetics excluded) to achieve that range. This has caused problems in diesel engines, but fewer polymers are better for all engines. The wide viscosity range oils, in general, are more prone to viscosity and thermal breakdown due to the high polymer content. It is the oil that lubricates, not the additives. Oils that can do their job with the fewest additives are the best. Very few manufactures recommend 10W-40 any more, and some threaten to void warranties if it is used. It was not included in this article for that reason. 20W-50 is the same 30 point spread, but because it starts with a heavier base it requires less viscosity index improvers (polymers) to do the job. AMSOIL can formulate their 10W-30 and 15W-40 with no viscosity index improvers but uses some in the 10W-40 and 5W-30. Mobil 1 uses no viscosity improvers in their 5W-30, and I assume the new 10W-30. Follow your manufacturer's recommendations as to which weights are appropriate for your vehicle. | ||
| James M. Reed (Utahdog2003) Member Username: Utahdog2003 Post Number: 94 Registered: 03-2004 |
what's the source there? | ||
| Curtis N (Curtis) Dweb Lounge Member Username: Curtis Post Number: 1382 Registered: 05-2002 |
Chris - The oil is probably not going to resolve the valve issue, but synthetics are still a good idea. Run the rig a little harder and quit being easy on it. Like Dean said, getting up to 4-5K is not a bad thing. Peter - The fuel scale measurements are different in the US - not necessarily the fuel. I forget the specifics, but the there is a difference - RON, RAN, RIN, Rantantan. Ah hell. I forget, but a 98 in Austrailia is about the same as a 92/93 here. | ||
| John Parker (Jparker) New Member Username: Jparker Post Number: 9 Registered: 02-2004 |
I'm guessing that yall are also from the South. On my 97 Range Rover, I've already done 3 valve jobs, the last one was about a year and a half ago. About 6 months ago, i was talking to the dealership manager in Nashville TN, and he told me that this problem is much more common in the South than anywhere else in the world. He said it has something to do with the gas around here. He did say that they seem to have the problem under control, and i wouldn't need another one. I was sort of skeptical about that at first, but its been a year and a half, and my engine runs great, without any symptoms of buildup. But, when the Check Engine light comes on, try using some of that fuel system cleaner fuel additive. You can get that at just about any gas station. Before my last valve job, i did this once the check engine light came on, and after about 4 tanks, the light went out. I kept using the additive every tank, and the light didn't come back on again for about 6 more months. Then, i finally had the valve job. ~jp | ||
| Shaun Power (Shaunp) Senior Member Username: Shaunp Post Number: 284 Registered: 05-2003 |
Australian fuel is rated in RON,normal unleaded is 91 ron, prem is 95 and the High density fuels like Shell Optimax, or BP ultimate are 98. Optimax is the control fuel for most Australian racing cars. | ||
| eric johnson (Eric2) Senior Member Username: Eric2 Post Number: 338 Registered: 05-2003 |
U-Dog - Source is...(crap, I knew someone was gonna' ask me for that'....just a minute)......Here 'tis - www.atis.net/oil_faq.html It's the Ed Hackett section, I used to know the man. | ||
| KC Jacob (Kcjacob) New Member Username: Kcjacob Post Number: 24 Registered: 02-2003 |
Does this mean that if I am using Mobil 1 5W-30, I will be messing up my engine? Should I switch to a 10W-30? Pardon me if I come across as a chump. | ||
| James M. Reed (Utahdog2003) Member Username: Utahdog2003 Post Number: 106 Registered: 03-2004 |
Thanks Eric | ||
| eric johnson (Eric2) Senior Member Username: Eric2 Post Number: 341 Registered: 05-2003 |
Chumpmeister,  AMSOIL can formulate their 10W-30 and 15W-40 with no viscosity index improvers but uses some in the 10W-40 and 5W-30. Mobil 1 uses no viscosity improvers in their 5W-30, and I assume the new 10W-30. However, this article is several years old. All Amsoil USED to be made with PAO base stock, which is a Class IV base. Now the XL-7500 series oil is made with class III base stock. Class III starts out as petroleum, but with all the refining it goes through, Class III is now considered a synthetic. I believe Mobil 1, Castrol, Valvoline, and the other usual suspects use the Class III base stock for their formula. Not all Class III base stock is equal...some are better than others. The Amsoil XL-7500 series formula was changed to compete in the "Speedee Lube" oil change market. They could not ask a buck or two more per quart compared with Mobil 1. The rest of Amsoil oils are formulated to last for 25K miles, hence the PAO base. I personally wouldn't go that long, but it looks like you could if you had to. So it looks like if you are using synthetics and going to change oil every 3-5 thousand miles, the lower price of the XL-7500 series would make sense. Depends how much lower though. |
