Motor flush

[uss2defiant]

i switched to synthetic recently, no significant difference.

 

[mindbomb]

I do drive very moderately in the city - the KJ is no sports car so I don't particularly enjoy accelerating strongly for no reason, I use cruise on highways.
My average mpg is nowhere close to what you're getting.
I only have logs of what was replaced 10k miles ago - no diff fluids in this list so I don't know when was it replaced although I didn't feel any slippage.

trans fluid/filters/sparks were indeed replaced 10k miles ago, and now I am replacing oil/filter. Was about to use this LIQUI MOLY - Motor Oils, Additives, Car Care - Products - Pro-Line Engine Flush
but this thread advised me against it.

I'll recheck my tires pressure (its quite worn) - will be replaced to new ones soon after I install a lift kit, hopefully after finding the cause for the poor gas milage.

What is your driving style like (and be HONEST)? Everyone always says they drive normal... or "not too aggressive".. they're fibbing. lol.

How high does the engine rev while you accelerate normally? Are you a half throttle at every green light kinda guy?

I drive like an old man who's pissed off that his paper boy was 3 minutes late that morning... people pass me because I don't accelerate as fast as they do. I get to speed, I just aint in a hurry to do it (I still accelerate quickly enough to not slow down traffic or cause safety issues). My engine rarely goes past 3,000rpm on a normal city/rural highway acceleration. Expressway, different story, get your **** up to speed!

How about your differential fluids? Changing mine seemed to help my mpg. New trans fluid and filter recently, like in the past 30-50k miles? If the trans is slipping slightly, or not applying all the power to the axles, the engine is going to have to work harder for the same amount of acceleration.

That being said, I avg 18.6-19.7mpg city/55mph highway. Routinely see 20-21.5mpg at 70mph on the expressway. Higher when I'm cruising along on a 55mph rural highway. I use cruise control when possible, and coast to stop lights (even yellow ones) when appropriate.

Also check and maintain your tire pressures.. even just 2psi off is enough to make a difference.

 

[JasonJ]

Hmm. ok. Well, good luck. Wise move steering clear of any oil additive. There are plenty in the oil already.

We already had the argument over better or worse fuel efficiency with worn tires, so not gonna touch that again...

Diff fluids shouldn't make a 4-5mpg difference... something's off. Engine oil's not gonna do it either.. I leak/burn most of mine through a valve cover gasket and use Walmart Supertech 5w30... not horrible oil, but not synthetic or even name brand.

What do you run your tire pressures at? I run 33psi front and back all year on 245-70-16 All terrains.

 

[CalcityRenegade]

Hmm. ok. Well, good luck. Wise move steering clear of any oil additive. There are plenty in the oil already.

We already had the argument over better or worse fuel efficiency with worn tires, so not gonna touch that again...

Diff fluids shouldn't make a 4-5mpg difference... something's off. Engine oil's not gonna do it either.. I leak/burn most of mine through a valve cover gasket and use Walmart Supertech 5w30... not horrible oil, but not synthetic or even name brand.

What do you run your tire pressures at? I run 33psi front and back all year on 245-70-16 All terrains.

Here are a few engine problems that hurt fuel economy:

- missing or defective thermostat, causing low operating temperature

- clogged intake manifold exhaust crossover passage (for heating intake manifold)

- engine misfire caused by bad spark plug, ignition wire, coil, dist. cap or rotor

- late ignition timing

- bad vacuum advance unit (common in old cars)

- stuck centrifugal advance mechanism in distributor (needs oil occasionally)

- bad tension adjustment of centrifugal advance springs

- defective oxygen sensor (causes rich mixture)

- defective coolant temp. sensor for engine computer (causes rich mixture)

- worn timing belt (may cause rich fuel mixture in fuel injected cars with a MAP sensor)

- incorrect timing belt installation (timing marks should line up)

- sticking or poorly adjusted carburetor choke (causes rich mixture)

- dirty air filter on an engine with a carburetor (causes rich mixture at high power)

- clogged or defective PCV valve

- incorrect valve clearance (especially if too tight)

- high performance camshaft installed (not efficient at low power)

- worn valve guides (makes fuel mixture too lean at low power)

- vacuum leak from bad vacuum hoses or intake system gaskets (causes lean mixture)

- dirty fuel injectors

- bad fuel pressure regulator

- bad MAP sensor for fuel injection

- leaking intake duct between air flow sensor and throttle body

- too much alcohol in gasoline with old car (requires carb. modification for correct mixture)

- rusted or missing exhaust heat stove or pipe for heated air intake

- loss of compression pressure due to worn rings or leaking valves

- sticking EGR valve (causes rough idling and rich mixture on some engines)

- exhaust backpressure caused by clogged catalytic converter, muffler or crushed pipe

- stuck exhaust manifold valve for some V type engines. Intended for fast warm up.

More engine problems:

- high idle speed

- high fast idle speed when cold

- incorrect idle mixture adjustment (carburetor or fuel injection)

- leaking fuel line or carburetor (dangerous too)

- clogged jets (calibrated holes) inside carburetor

- defective power valve in carburetor

- worn camshaft lobes

- high alternator voltage (should be about 14 volts when warm)

- high oil level (interferes with crankshaft movement)

- high oil pressure (relief valve stuck or has wrong spring)

- stuck cooling fan clutch (runs fan when not needed)


Problems that increase rolling resistance:

- sticking disk brake calipers

- tight drum brake adjustment

- warped brake rotor or drum

- sticking parking brake cable

- incorrect wheel alignment, front or rear (check tire wear)

- worn suspension joints (ball joints, steering joints)

- worn control arm bushings (changes wheel alignment)

- worn or incorrectly adjusted wheel bearings

- leaking grease seals for wheel bearings

- use of snow tires when not needed

- leaking tires, causing loss of pressure

- warped tires

- bent rims, causing car to shake

- poor wheel balance, causing shaking at high speeds

- worn shocks or springs (forces driver to brake more)


Automatic transmission problems:

- wrong fluid level

- incorrect throttle valve cable adjustment

- bad vacuum modulator or vacuum hose to modulator

- sticking valves in valve body, causing delayed shifts; changing transmission fluid may help

- failure of torque converter to lock up (if equipped with lock-up torque converter); it should engage at 30-55 MPH, reducing engine speed about 10%

- stuck stator clutch in torque converter


Manual transmission problems:

- wrong fluid level

- excessive oil viscosity

- bad bearings

- failure to engage one or more gears


Differential problems:

- wrong fluid level

- excessive oil viscosity

- bad bearings

- high ratio ring and pinion gear set installed for racing


:hidesbehindsofa:

 

[BorincanoKJ]

When i got the SUV was 72 km, since then.
When I do the oil change i always used Mobil Super 10W-30.

Thanks for your advice.

 

[tjkj2002]

Don't flush it. Any "sludge" that's sealing a gasket will cause leaks.


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On top of that, the synthetic will truly clean up the "gunk" and cause it to block and pickup tune in the pan. I have a new engine and I've put synthetic in it ever since I had it put in. Always stick with same brand of oil and type IMO

That is a myth that you should always stick to the same oil and switching will cause leaks.30 years ago with cork gaskets and actual rubber seals yes it would but nowdays it changes nothing.

Reason some may notice leaks forming after switching to synthetic is due to syn oil ability to flow better under high pressure when the engine is cold making the very slow leak to get much,much worse after switching.

Here are a few engine problems that hurt fuel economy:

- missing or defective thermostat, causing low operating temperature

- clogged intake manifold exhaust crossover passage (for heating intake manifold)

- engine misfire caused by bad spark plug, ignition wire, coil, dist. cap or rotor

- late ignition timing

- bad vacuum advance unit (common in old cars)

- stuck centrifugal advance mechanism in distributor (needs oil occasionally)

- bad tension adjustment of centrifugal advance springs

- defective oxygen sensor (causes rich mixture)

- defective coolant temp. sensor for engine computer (causes rich mixture)

- worn timing belt (may cause rich fuel mixture in fuel injected cars with a MAP sensor)

- incorrect timing belt installation (timing marks should line up)

- sticking or poorly adjusted carburetor choke (causes rich mixture)

- dirty air filter on an engine with a carburetor (causes rich mixture at high power)

- clogged or defective PCV valve

- incorrect valve clearance (especially if too tight)

- high performance camshaft installed (not efficient at low power)

- worn valve guides (makes fuel mixture too lean at low power)

- vacuum leak from bad vacuum hoses or intake system gaskets (causes lean mixture)

- dirty fuel injectors

- bad fuel pressure regulator

- bad MAP sensor for fuel injection

- leaking intake duct between air flow sensor and throttle body

- too much alcohol in gasoline with old car (requires carb. modification for correct mixture)

- rusted or missing exhaust heat stove or pipe for heated air intake

- loss of compression pressure due to worn rings or leaking valves

- sticking EGR valve (causes rough idling and rich mixture on some engines)

- exhaust backpressure caused by clogged catalytic converter, muffler or crushed pipe

- stuck exhaust manifold valve for some V type engines. Intended for fast warm up.

More engine problems:

- high idle speed

- high fast idle speed when cold

- incorrect idle mixture adjustment (carburetor or fuel injection)

- leaking fuel line or carburetor (dangerous too)

- clogged jets (calibrated holes) inside carburetor

- defective power valve in carburetor

- worn camshaft lobes

- high alternator voltage (should be about 14 volts when warm)

- high oil level (interferes with crankshaft movement)

- high oil pressure (relief valve stuck or has wrong spring)

- stuck cooling fan clutch (runs fan when not needed)


Problems that increase rolling resistance:

- sticking disk brake calipers

- tight drum brake adjustment

- warped brake rotor or drum

- sticking parking brake cable

- incorrect wheel alignment, front or rear (check tire wear)

- worn suspension joints (ball joints, steering joints)

- worn control arm bushings (changes wheel alignment)

- worn or incorrectly adjusted wheel bearings

- leaking grease seals for wheel bearings

- use of snow tires when not needed

- leaking tires, causing loss of pressure

- warped tires

- bent rims, causing car to shake

- poor wheel balance, causing shaking at high speeds

- worn shocks or springs (forces driver to brake more)


Automatic transmission problems:

- wrong fluid level

- incorrect throttle valve cable adjustment

- bad vacuum modulator or vacuum hose to modulator

- sticking valves in valve body, causing delayed shifts; changing transmission fluid may help

- failure of torque converter to lock up (if equipped with lock-up torque converter); it should engage at 30-55 MPH, reducing engine speed about 10%

- stuck stator clutch in torque converter


Manual transmission problems:

- wrong fluid level

- excessive oil viscosity

- bad bearings

- failure to engage one or more gears


Differential problems:

- wrong fluid level

- excessive oil viscosity

- bad bearings

- high ratio ring and pinion gear set installed for racing


:hidesbehindsofa:

Just to be clear 50% of the above does not apply to any vehicle made past 1996 and 95% of the remaining 50% will turn on the check engine light informing you have a issue that is reducing emissions(and possibly mpg's and performance).

 

[teeje]

I didn't say switching brands will cause leaks. I said switching to a synthetic oil is not recommended for a high mileage engine that's never had it in its life. If a gasket was leaking and sludge stopped it from doing so, yes it can cause leaks


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[tjkj2002]

I didn't say switching brands will cause leaks. I said switching to a synthetic oil is not recommended for a high mileage engine that's never had it in its life. If a gasket was leaking and sludge stopped it from doing so, yes it can cause leaks


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That is false and been false for 30 years.If it leaks right after switching you had the leak before just the syn oil flows better at cold temps getting past the leak point which the dino oil would not pass through till hot but by then the metals expanded enough to prevent that.

Same leak concept that modern cooling systems are plagued with due to plastic parts being used and sometime will only leak at a certain temp but not at cold or hot temps but in-between when the 2 different materials are expanding at different rates.

 

[JasonJ]

... i always used Mobil Super 10W-30.

Thanks for your advice.

That seems a touch thick, regardless of mileage. Unless you drive in 90+ degree environments.. then perhaps it is warranted.

I've lost fuel efficiency on vehicles from too high of an oil viscosity before. Have you tried 5w30 or 5w20?

 

[mindbomb]

I'm gonna use this one for the KJ (117k miles)

You must be registered for see images attach

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[tjkj2002]

I'm gonna use this one for the KJ (117k miles)

You must be registered for see images attach

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Can't go wrong with that,just make sure to use the matching Mobil1 oil filter and change it at regular intervals(not 10k or once every 5 years like some).

 

[Conundrum2006]

I didn't say switching brands will cause leaks. I said switching to a synthetic oil is not recommended for a high mileage engine that's never had it in its life. If a gasket was leaking and sludge stopped it from doing so, yes it can cause leaks


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I'm not so sure about modern engines. I've had Ford Mustang 5.0, a 318 5th ave, and my old 2.8 jeep where this was true, or at least they leaked worse with synthetic. Swapped back to old Dino oil and they were happier. 4.0 jeep liked to leak no matter what. As I replace the seals it doesn't matter which oil is used.

I think when the seals are gone they are gone, maybe the old seals are tired just didn't work well with the new synthetic and it's a big job to make right. Modern engines I've had much better luck with.

There are also seal restoring additives. I've heard good things about them. I'm using one brand in a 4.0 jeep to see if it does anything to help the rearmain. Some swear by them. I just don't know.

Far as the sludge sealing the leaking gaskets I can say from the heavily gunked up 3.7 I took apart this it true, but it might take a while for the enough gunk to be removed to make a leak start.


Btw 10-30 is kind of thick for these engines, if you're really worried about mpg try 5-20 it what the manufactures settled on to help mpg. Personally I like 5-30 but use 5-20 if I get a better deal.


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[tommudd]

I'm not so sure about modern engines. I've had Ford Mustang 5.0, a 318 5th ave, and my old 2.8 jeep where this was true, or at least they leaked worse with synthetic. Swapped back to old Dino oil and they were happier. 4.0 jeep liked to leak no matter what. As I replace the seals it doesn't matter which oil is used.

I think when the seals are gone they are gone, maybe the old seals are tired just didn't work well with the new synthetic and it's a big job to make right. Modern engines I've had much better luck with.

There are also seal restoring additives. I've heard good things about them. I'm using one brand in a 4.0 jeep to see if it does anything to help the rearmain. Some swear by them. I just don't know.

Far as the sludge sealing the leaking gaskets I can say from the heavily gunked up 3.7 I took apart this it true, but it might take a while for the enough gunk to be removed to make a leak start.


Btw 10-30 is kind of thick for these engines, if you're really worried about mpg try 5-20 it what the manufactures settled on to help mpg. Personally I like 5-30 but use 5-20 if I get a better deal.


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Anything I have owned in the past 20-25 years got switched to Mobil 1 and never had an issue with leaking / seeping etc
Included everything from brand new to ones with 100,000 miles plus
maybe just lucky:gr_grin:

 

[JasonJ]

I've switched engines with 180,000 miles over to synthetic with no issues. That was a 91 Mazda 1.8DOHC that I ran the PISS out of.. 6-7k rpm daily.

Also switched to synth in my old Ranger way back when.. it had 318,000 miles on that 2.0 Pinto OHC engine. It did just fine.

If your seals and gaskets are gonna leak, they are gonna leak..

 

[kage860]

I've been running synthetic since I started reading the maintenance forum bitog.com. It doesn't really cost all that much more when you're changing it yourself and it does last longer and clean/lubricate better.

Pennzoil Platinum can be had real cheap right now at walmart $22.47-$10 rebate with free shipping.
5-Quart Pennzoil Platinum Full Synthetic Motor Oil (Various) - Slickdeals.net
Some say it's slightly better than Mobil 1 due to it being a "truer" synthetic. But at that point its splitting hairs, most synthetics are pretty good. Good viscosity / additives etc. I usually end up buying the name brand one that's currently on sale. Same thing as I do with coke/pepsi, lol.

 

[BorincanoKJ]

Hi JasonJ
I use 10w-30 beacuse i live in the Caribbean the temperature is between 70-90+