answersLogoWhite
Auto Parts and Repairs
Car Sounds
Fuel and Engines
Toyota Tacoma

What would cause loud engine knocking for a few minutes only when the engine is cold?


Top Answer
User Avatar
Wiki User
2015-07-14 16:46:14
2015-07-14 16:46:14

Is there any smoke when you first start it? what is happening is the valve seals are probably worn and letting the oil seep past them. when your engine is first started it has no oil or very little oil at the top of the engine, thus causing the knocking noise. could be more but this is a most likely . oh and is you haven't changed your oil every 3,000 miles you had beeter start doing it....

knocking sounds usually come from bottom of engine try a better quality and correct viscosity oil

does it stop after warming up? could be faulity engine lifters. lpaws45.

-------------------------------------------------------------------------------------------------------------

lpaws45 is pretty accurate for most engines with a genuine engine knock. But on a Mitsubishi Endeavor, my guess is you aren't using premium (91 octane) fuel 100% of the time as recommended by Mitsubishi. This creates carbon build-up on top of the pistons which in turn creates a knocking sound very similar to a lower-end engine knock. This knock will eventually occur at all times, hot or cold. The cure is to have an engine decarbon procedure performed (having a professional run a solvent through the intake vacuum) and start using premium fuel. The added fuel mileage from using premium with a 3.8 liter Mitsubishi V6 will more than pay for the extra cost.

Related Questions

User Avatar

can you elaborate? engine noise? stationary/moving? ticking, tapping or a definite knocking?

User Avatar

Having a bad rod bearing could cause a truck to make a loud knocking noise and shake when driving at high speeds. The engine having a coolant leak or an engine timing problem could also cause the knocking noise.

User Avatar

A hole in the muffler would cause a knocking sound in your muffler. A loose exhaust pipe can also cause a knocking noise.

User Avatar

maybe the carberator i dont know im not a machanic or anything

User Avatar

I would recommend taking it to a mechanic and have them listen to it. Everyone's definition of "knocking" is slightly different. Try not to drive it for too long; engine knocks can usually cause pretty severe damage to an engine.


Copyright © 2020 Multiply Media, LLC. All Rights Reserved. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply.