Question about 1991 Mitsubishi Montero

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Low idle and low oil pressure and now valve clatter in my 1991 montero. is it feasible to replace the oil pump, if that is the problem, on a vehicle that has over 250,000 miles? i'd like to keep this vehicle. it's great off road. if i do need a new oil pump should i just drop a new motor in it? where is the best place to look for motor and/or parts?

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Great truck I am now on my second with 280K miles. The lower oil pressure is probably a combination of a worn pump and now worn bearings with greater clearances.. thus less pressure. The oil pump on your 3.0 V6 is located behind the front crank pulley. To access it I'd strongly recommend pulling the entire engine as the oil pan will need to be removed and the fron of the engine will have to go too. Your engine is found in many cars including the dodge stealth and Mitsubishi 3000GT. I belive the years to 1992 run the same pistons and compression after which they run at 10-1 and use a knocks sensor which your truck does not use. I would locate a good used block and check its clearances and cylinders if it requires rebuild I'd have this done and then fit with rebuilt heads or remove your engine and have the short block rebuilt and have the heads fitted with new valve guildes and seals (have valves gound too) You can check ebay or craiglest for a block see link:

for rebuild kits and such, I love my Montero she has the aerodynamics of a barn but never lets me down. It is a lot of work but in my view worth the time to do.
I hope this may have helped,

Posted on Oct 10, 2009


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Where is the oil pump on a 1997 mercury sable 3.0 engine think its weak as I hear valves chatter and changed oil filter it was only half full of oil is this normal

Half full is not normal. You may have leak or burn. Clatter is usually the hydralic valve lifters. Does it quiet down after it's been running a while? What is the oil pressure?

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Did you check the oil pressure switch? Are you getting a low oil light?

Apr 28, 2017 | 1991 Saab 900

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Noise sometimes in the engine

Hi there:
First I suggest to check this information about "engine noses"...
A clicking or tapping noise that gets louder when you rev the engine is probably "tappet" or upper valvetrain noise caused by one of several things: low oil pressure, excessive valve lash, or worn or damaged parts.

First, check the engine dipstick to see if the oil level is low. If low, add oil to bring it back up to the full mark. Is the engine still noisy? Check your oil pressure. A low gauge reading (or oil warning light) would indicate a serious internal engine problem that is preventing normal oil pressure from reaching the upper valvetrain components. The cause might be a worn or damaged oil pump, a clogged oil pump pickup screen or a plugged up oil filter. Using too thick a viscosity of motor oil during cold weather can also slow down the flow of oil to the upper valvetrain, causing noise and wear.

Worn, leaky or dirty lifters can also cause valvetrain noise. If oil delivery is restricted to the lifters (plugged oil galley or low oil pressure), the lifters won't "pump up" to take up the normal slack in the valvetrain. A "collapsed" lifter will then allow excessive valve lash and noise.

If you can rule out lubrication-related problems as a cause, the next step would be to remove the valve cover(s) and check valve lash. On older import engines, mechanical lifters require periodic valve lash adjustments (typically every 30,000 miles). Too much space between the tips of the rocker arms and valve stems can make the valvetrain noisy -- and possibly cause accelerated wear of both parts.

To measure (and adjust) valve lash, you need a feeler gauge. The gauge is slid between the tip of the valve stem and rocker arm (or the cam follower or the cam itself on overhead cam engines) when the piston is at top dead center (valve fully closed). Refer to a manual for the specified lash and adjustment procedure. Also, note whether the lash spec is for a hot or cold engine (this makes a big difference!).

On engines with hydraulic lifters, oil pressure pumps up the lifters when the engine is running to maintain zero lash in the valvetrain. This results in quiet operation. So if the rocker arms are clattering, it tells you something is amiss (bad lifter or worn or damaged parts) or the rocker arms need adjusting.

Inspect the valvetrain components. Excessive wear on the ends of the rocker arms, cam followers (overhead cam engines) and/or valve stems can open up the valve lash and cause noise. So too can a bent pushrod or a broken valve spring.

Usually bad news. A deep rapping noise from the engine is usually "rod knock," a condition brought on by extreme bearing wear or damage. If the rod bearings are worn or loose enough to make a dull, hammering noise, you're driving on borrowed time. Sooner or later one of the bearings will fail, and when it does one of two things will happen: the bearing will seize and lock up the engine, or it will attempt to seize and break a rod. Either way your engine will suffer major damage and have to be rebuilt or replaced.

Bearing noise is not unusual in high mileage engines as well as those that have been neglected and have not had the oil and filter changed regularly. It can also be caused by low oil pressure, using too light a viscosity oil, oil breakdown, dirty oil or dirt in the crankcase, excessive blowby from worn rings and/or cylinders (gasoline dilutes and thins the oil), incorrect engine assembly (bearings too loose), loose or broken connecting rod bolts, or abusive driving.

Bearing wear can be checked by dropping the oil pan and inspecting the rod and main bearings. If the bearings are badly worn, damaged or loose, replacing the bearings may buy you some time. But if the bearings are badly worn or damaged, the crankshaft will probably have to be resurfaced - which means a complete engine overhaul or replacing the engine is the vehicle is worth the expense.

The cause here may be Spark Knock (Detonation) caused by an inoperative EGR valve, overadvanced ignition timing, engine overheating, carbon buildup in the combustion chambers, or low octane fuel.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Jun 21, 2012 | 2001 Mitsubishi Montero

1 Answer

I have a 2002 Grand am Gt 3400 engine.. Car ran fine, no problems..Went out to start it one afternoon and engine clattered very i turned it off right away.. took off the valve cover and i did...

The engine needs to be replaced. Clatter can be the main and rod bearings or the lifters. Lifters clatter with no oil pressure. Low or no oil pressure is usually bearings. Oil pumps rarely go bad, they are a very simple set up And work forever. I have never replaced a pump because it was bad. And running an engine for 30 seconds would not do that kind of damage. But running a long time low on oil will.

Jul 31, 2011 | Pontiac Grand Am Cars & Trucks

1 Answer

Just changed oil in kia sorento 06 manuel transmission oil light stays on and clatters

Hi there,

DANGER....this is telling you there is NOT enough oil pressure. The clatter you hear means inadequate oil is reaching the cams or lifters.

Can you confirm you have used the correct grade & viscosity of oil? Is oil leaking?

Please re-check the oil level again - allow vehicle to sit for 5mins, then check oil level on the ENGINE dipstick. If dipstick level is up to the full mark, then assume you have enough oil and let the engine idle for 5mins.

If the clatter remains, then suspect a problem with the oil pump, or oil filter causing a blockage.


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May 13, 2011 | 2006 Kia Sorento

1 Answer

1995 GMC Jimmy 3.5L HO - lots of engine clatter, very low oil pressure - 10-30 on dash gauge from idle to 3000 rpm, oil full. Oil pump problem or major repair??

if the noise is coming from the oil pan you may have bad rod bearings or main bearings or the oil pick up tube could have also came loose but since you have oil pressure im gonna say your looking at replacing or rebuilding the engine witch is a major repair.

Jan 19, 2011 | 1995 GMC Jimmy

1 Answer

No pressure. lights not guage. Where is the oil pump how much might the parts be?

if the oil pressure is actually low (and not just a false indication) then you should hear valve lifters making a clatter .. if they are not making noise then you might just have a bad oil pressure sending unit (small part that screws in) .. if you do hear clatter then in some cars the intake screen on the oil pump can be clogged with sludge ... that doesnt happen often with the caravan but possible if oil hasnt been changed for a long time ... the oil pump is located inside the crank case and service requires removal of the pan ... if you have valve clatter then driving the car can do a lot of damage if the problem is not fixed ... check the oil filter for damage or clogging ... of course check oil level. a milky appearence in the oil would indicate water in the oil (often a blown head gasket) ..

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It has low oil pressure, ticking sound,and loss in power

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2 Answers

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I have a 98 Ford Expedition,The valves clatter when you accelerate in drive,ive put octane booster in gas,still clatters. is it possible that the egr valve is not opening correctly?if so ill check and the...

Yes i agree this is a egr problem can you put vacuum to the egr valve while it is running to see if the idle drops if it does then the valve itself is good .Then check the dpfe evr solenoids :)

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