So, you think you're an engine guru?

[Galant306m]

the oil has nothing to do with it! How fast were you going when your timing belt snapped! cause that sudden stop of the valves could have messed up a valve guide which would cuase you to loose that oil! if you were at idle it wouldnt really be a problem but if your car was at a higher rpm you could have cracked a valave guide which would explain your oil loss!!

[laxinwarrior]

the oil has nothing to do with it! How fast were you going when your timing belt snapped! cause that sudden stop of the valves could have messed up a valve guide which would cuase you to loose that oil! if you were at idle it wouldnt really be a problem but if your car was at a higher rpm you could have cracked a valave guide which would explain your oil loss!!

Dude did you actually read any of the posts in this thread or are you just trying to get a #1 on your post count?

[manybrews]

and a prize for the winner....

I was just testing you guys, thus the name of the thread.

It's the valve seals on the exhaust side. I've already corrected the problem and no more smoke, no more oil consumption. Just a test

and my prize is?

[seth98esT]

and my prize is?

[eksz]

98ACR,
After your timing belt broke did you attempt to just replace the timing belt or did you decide to replace (rebuild) your head assuming it was damaged? Were there any signs of damage to the head? I ask because I have blown timing belts on my 94 ES 3 times without any apparent damage to head or pistons. I blew the timing belt once when I was doing at least 80MPH and another time when I was just idling. I know Mits says these are interference engines but I can't believe it given my experiences. Car now has 235K miles and still going strong. jjj

[manybrews]

98ACR,
After your timing belt broke did you attempt to just replace the timing belt or did you decide to replace (rebuild) your head assuming it was damaged? Were there any signs of damage to the head? I ask because I have blown timing belts on my 94 ES 3 times without any apparent damage to head or pistons. I blew the timing belt once when I was doing at least 80MPH and another time when I was just idling. I know Mits says these are interference engines but I can't believe it given my experiences. Car now has 235K miles and still going strong. jjj

all mitsu engines with more than 2 valves per cylinder are interference engines. Most of the 2 valve engines are interference as well.

if you broke a belt, you definitely had valve to piston contact.

[98ACR]

Yup, every exhaust valve in the head was bent at nearly a 90* angle. I wish I'd taken pics....quite impressive. I thought about replacing the whole engine at that point since there were some pretty nice indentions in the pistons but the rings were tight so I just went with the new head. It worked pretty well so far and the engine still runs as strong as ever.

[fuel]

pretty sure I know a thing or 2 about mitsu engines..... and you're NOT losing a quart every 500 because its 10w30.

I use ONLY 5w30 in all my cars, and im now on a second diamante with over 200,000 miles.

I use less than a quart every 1000 on one of them, and a quart every 2000 on the other.
no, the problem stems from either an improper repair, or something else. changing from 5w30 to 10w30 to 15w40 will have little to do with that.
truth is the thicker oils are generally bad for an engine.. they cause excess drag and wear, and usually will suffer a loss of milage and horsepower.

That may be the case if you are running something really thick like a 20W60 etc. Running a 10W40 will not put any more strain on your engine at all. Mitsubishi Japan specifies their 4G63s and 4G64s run on 10W40 or 15W40 from the early to mid-late 90s.

Thinner oil such as 5W30 or 10W30 doesn't protect as well up in the high rev range as say 10W40 generally - the thicker oil provides a better cushion between the crank and the bearings.

I know the American Mitsubishis do tend to specify a lower viscosity oil such as 10W30, or even in the case of the newer ones 5W20 (eep!) But as engines get older and the milage ticks up it is wise to change to a oil more which is more suitable.

Some oils are better than others, obviously an expensive 5W30/10W30 is going to protect better than a cheap 10W40 etc, but generally the thicker oils give better protection for the engine.

Also using a quart over 1000 miles isn't what I would call acceptable... surely the change to a decent quality 10W40 (which isn't even a thick oil by the way) will reduce the oil consumption therefore keeping running costs down.

I'm using Valvoline semi-synthetic 15W40 on my 6A12 V6 MIVEC Galants and I do my oil changes every 5000kms (3500 miles) apart and mine doesn't use a drop, and I have peice of mind when I rev it up to 8200rpm.

[manybrews]

That may be the case if you are running something really thick like a 20W60 etc. Running a 10W40 will not put any more strain on your engine at all. Mitsubishi Japan specifies their 4G63s and 4G64s run on 10W40 or 15W40 from the early to mid-late 90s.

Thinner oil such as 5W30 or 10W30 doesn't protect as well up in the high rev range as say 10W40 generally - the thicker oil provides a better cushion between the crank and the bearings.

im afraid thats a total myth.

you will easily get the same protection on todays cars with todays high-tech oils if you use the recommended low viscousity.
you will also get added performance.

I know the American Mitsubishis do tend to specify a lower viscosity oil such as 10W30, or even in the case of the newer ones 5W20 (eep!) But as engines get older and the milage ticks up it is wise to change to a oil more which is more suitable.

The only car mitsu has ever recommended 10w30 for is the EVO.
everything else is 5w30, 5w20, or (similar to ALL japanese companies), 0w20.

Some oils are better than others, obviously an expensive 5W30/10W30 is going to protect better than a cheap 10W40 etc, but generally the thicker oils give better protection for the engine.

as long as pressure is built, you have protection. Mitsu has never had any type of oil system issues, and easily maintains high oil pressure throughout the life of their engines.

Also using a quart over 1000 miles isn't what I would call acceptable... surely the change to a decent quality 10W40 (which isn't even a thick oil by the way) will reduce the oil consumption therefore keeping running costs down.

actually, 1 quart in 1250 miles is acceptable on a new car, and that spec is pretty much industry standard.

I'm using Valvoline semi-synthetic 15W40 on my 6A12 V6 MIVEC Galants and I do my oil changes every 5000kms (3500 miles) apart and mine doesn't use a drop, and I have peice of mind when I rev it up to 8200rpm.

synthetics are a waste of money for 99 percent of the people that use them... its primarily marketing that makes people buy it.
It is useful ONLY in extreem temperature situations (both low and high). Most mitsus can never reach the high oil temps that would require the use of synthetic oils.

And semi-synthetics are a complete waste. You get none of the benefits of the synthetic oils, but you manage to get a massive price premium.
if you must use synthetic (which is not needed for most of the people that use it), use full synthetic.

[fuel]

Yeah I realise semi-synthetic isn't true synthetic oil. I paid under NZ$50 for 12L of that 15W40 oil, and it meets the SM specification.

1 quart is roughly one liter right? 1250 miles is about 2000km. I really dont think 1L over 2000kms is acceptable for a new car?!

Also ACR's car is far from 'todays' car. It's over ten years old and has 175k on the clock. The 4G64 engine is also over 20 years old.

Both the users manuals for my 7G Galants recoomend 5W30, 15W40 or 15W50 depending on the climate.

On a worn bottom end with worn bearings I know I would want a good oil to protect them. I feel and fear that switching to 5W30 is just going to be too thin and may run the risk of damaging a bearing at the amount of revs I pull on my V6.

I have experienced first hand the results of big end bearing failure on my V6 and it isn't pretty - if you haven't seen it yet look at my post in this section named '6A12 rod snapping goodness'.

[bmxmike]

The reason that oil viscosities have gotten thinner is because bearing clearances have become smaller. Using thicker oils will interfere with oil flow and the oil pressure will increase. In a worn engine it may be okay to increase the viscosity of the oil because the bearing clearances have become larger. So in new engines it is better to use a 5w30 over a 10w30 unless you do have a older vehicle.

As for synthetic..It is also a good choice if your vehicle is operated in extremely cold climates. It has higher resistance to breakdown caused by heat and it flows better in extreme cold. Unfortunately for the synthetic oil industry there is virtually no advantage to using synthetic oil in a non-high performance engine that is operated in moderate climates. You probably could go a bit longer between oil changes with a synthetic, i.e. following the normal service schedule even if you fall into the severe service category, but I wouldn't advise this. In short, synthetic may give you the peace of mind of knowing that you are using an oil that is far better than necessary for your vehicle, but it won't reduce wear or extend the life of the engine. The mistake some people make it to wrongly extrapolate these benefits onto normal engines operated in mild climates, with the ultimate lack of any knowledge being manifested with statements such as "synthetics provide 'Peace of Mind,' or 'Cheap Insurance,'" or other such nonsense.

[fuel]

Yes I am agreeing 100% that 5W30 would have been great when the car was NEW, back in 1994 or whenever 98ACR's car was built. Back then there wasn't really much of a range of oils anyway, and they definitely weren't as good as they are today. But comparing his ES with a car of 'today' is like comparing apples with oranges!

His car is 13 years old, with 175K on the clock! It's safe to say that the tolerances in that engine are not the same as they were when the car was new, or even when the car was five years old with say 50K on the clock.

I have owned nothing but high milage cars with the exception of one, and I have found the best oils to use are the oils more suited to a higher milage engine. My old 89 Galant with 410,000kms (250k + miles) was run on 20W50 as it did used to drink a bit of oil. However having said that the engine which was in it (a 4G37 SOHC carb) dates back to the 70s in design so it would have been fine. The Sirius series engines (4G6x) originated from 1980, back when they were designed to run on 20W40 or something similar.

I reckon the best thing you can do for an engine oil wise is keep up with frequent changes with a good quality oil which is most suited for your climate and engine condition. 5W30/10W30 would have been fine for an engine even of old age, but if its getting to the point where it IS consuming alot of oil, it makes sense to change to an oil which wont be consumed as much - that's the point I'm trying to make.

[bmxmike]

Well thats what im saying that anything older or anything that has anyengine wear should probably go with a 10w40 or what ever higher number you want. And most older vehicles need the 10wXX because they didnt have the wide ranges. Also thats why in most mechanic shops they use 10w40 on almost any car they service for oil. Cause 10w40 is seen as good for all and most older vehicles will only take it so its cheaper for them to carry it in bulk. Me myself im switching over to a 10w40 in my next oil change cause im in the 90k range. Also when changing oil, it is a good idea to change the filter. Most people say every other oil change. Well that was okay back in the day of SAE 30 and so, but if you use a Detergent oil, it cleans the soot off the internal engine parts and suspends the soot particles in the oil. These particles stay in the oil till it is changed. This is what makes your oil darker, and it doesn't harm the oil but once it has reached its limit it cant clean the soot. So all this is flowing through your system. This is why its a good idea to changer you oil. Unless you do use the SAE 30 or whatever weight. As these normally dont contain the detergents. So the filter is not collecting as many particles.

~I'm goin to go ahead and make a topic for this cause its kinda getting away from the enine and more into oil choices.

[fuel]

Yeah I change my filter every oil change with a genuine Mitsubishi filter. Although I might make the switch to Fram filters soon, purely to keep expenses down at the frequency I change my oil.

[bmxmike]

Ya me to, i always switch my oil filter out. Im changing to a new one now though cause im changing to a 10w30 since im starting to bet about 90k...

[DOHCstunr]

i used mobil one 10w30 w/ either a oem filter, or a mobil one filter, on my 1994 GS 2.4 dohc engine fromm day one.
as did the previos owner from the day it was driven off the showroom floor and sam swope mitsubishi(as shown in the maintenance history)

i drove thhe shit out of it. i literally woudl redline every gear all day long, i was younger, i drove like an asshole, and i was always on the road, between school work, girlfriends, family, sports. i probably averaged 200 stop and go miles a day.
and i'm serious when i say i beat on it all day long.

only precautions i ever took, were to keep the rpms low for the first 10 miles of driving to keep the oil pressure from gettign to high, until the oil was up to operating temperature. as well as no less than a 20 second cool down after hard driving, or very easy low rev driving for the last half mile or so of each trip in an effort to lower oil temps.

and of course changing my oil and filter every 3k to 3500 miles.


after it was all said and done, and i decided to swap out my engine for the 4g63t,

i sold my motor to peanotation, he recieved it, dissasembled it and took it to the machine shop. the oil pan was spotless mind you. none of this sludge you awlays hear about.

amazingly, the machinist measured ever single clearance was to oem spec.
the rod bearings, main bearings, even 3 out of 4 cylinders were perfect and didn't need so much as a .01 over bore
the #3 was ever so slightly out of round.
and which i hear isn't all that uncommon.

but at 186,000 miles of hard high rev driving. the engine is nearly as solid as it was when it came off the assembly line.

no snake oil additives, no majic name brand oils,

[bmxmike]

Ya im only changing from 5w to 10w. Im stayin with Mobil One just want something a little thicker.

[fuel]

Difference in thickness between 5W and 10W is minimal, at least at operating temperature anyway. The 5W just refers to the viscosity when the oil is cold - ie when you first startup in the morning. The only benefit to a 5W over a 10W is in the winter if you live in a really cold place. The 5W would also have more additives added to the base blend to have a broader multigrade viscosity.

[frag_daddy_2007]

I thought that i had an oil leak in my heads for a while, but i realized later that it was leaking at my oil pressure sending unit. when it comes to lost oil, nothing is out of reach...