engine noise


Old 11-16-08, 07:39 AM
Thread Starter
Join Date: May 2007
Location: ga
Posts: 60
engine noise

i just bought a 1996 isuzu rodeo yesterday and i runs but has a loud tapping noise and smokes fairly bad the guy i bought i from said it had some problems but he didnt know what they were he had a new raditor and a new heater core put in any one have any ideas of what the problem may be thank you
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Old 11-16-08, 09:17 AM
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,770
It's probably due for a major (overhaul). The oil burning is probably coming from the upper end (rings or valve seals). The tapping could be lifters (worn,stuck,or no oil), or wrist pins (new pistons/wrist pins), or rod knock (lower end) or excessive main bearing play (redo the crank and lower end), or piston slap (bore cylinders = new pistons, rings).

I think I would look for a salvage yard engine.
Old 11-16-08, 09:21 AM
Join Date: Nov 2008
Location: Texas
Posts: 171
I am no expert, nor do I have any top end engine re-build experience. But, after admitting that I would guess, if the tapping is not too loud, I would guess a sticky valve or a worn out valve spring. Maybe a valve is not operating correctly and this is allowing some oil to leak into a cylinder and thus burning with the gas and that equals smoke.
A loud noise may equal a bad piston and if the piston ring is bad--more smoke.

Does it run smooth or rough?
Old 11-16-08, 12:01 PM
Thread Starter
Join Date: May 2007
Location: ga
Posts: 60
it runs smooth and it has 146000 miles on it ill probley just swap the engine is it hard to swap an engine in a 1996 isuzu rodeo
Old 11-16-08, 05:28 PM
Join Date: Nov 2008
Location: AZ
Posts: 4
Good info posted for you so far.

Other possibilities (which are easier fixes and less expensive):

1) Exhaust leak- these are usually pretty easy to isolate and fix. Does the tap increase with RPMs? Could be a leak at the exhaust manifold to block or maybe a cracked manifold.

2) Often overlooked as a source of a "tap" is a bad water pump. It may still move water and might not seep water out the seep hole (a sign of a bad H2O pump) but the bearings inside might be shot which will cause an annoying tap sound. On that note, is it leaking any coolant/water?

Try to isolate where on the engine the sound is coming from, that will make it much easier to help find your problem.

Other things to consider for a "tune up" for your new ride (all of which are easy to do yourself and not expensive):
New spark plugs (properly gapped), spark plug wires, distributer cap, fuel filter, air filter, brake pads and turn the rotors and/or drums, bleed the brakes, top off all fluids, balance and rotate the wheels...just some ideas. The main thing for now is to get the braking system in order just incase you need them to stop you in a hurry. You never know how a previous owner kept up the braking system

If the previous owner put a new radiator and heater core in then he was probably chasing an overheating problem. Does it over heat? If so Maybe a head gasket should be on that list too. I hear a lot of those rodeos "clicking," if its the same sound that I hear on a lot of them then it is likely a lifter issue. Burning oil and smoking is a piston ring issue. What color is the smoke?
Old 11-19-08, 07:02 PM
Thread Starter
Join Date: May 2007
Location: ga
Posts: 60
it was over heating dont know if it still does have not drove sine i bought it the oil in it is like a tan color and smells like gas it smokes really bad and the smoke it white
Old 11-20-08, 10:31 AM
Join Date: Nov 2008
Location: Picardy, France
Posts: 14
white smoke!!! I know

Hi Fast
This sounds like a faulty head gasket.
Water is mixing with oil and leaking in the cylinders this is why you are "steaming".
This is not a terrible breakdown.
You have to undo the head.
Check if there are no cracks. If you find cracks it must be changed.
If there are no cracks, as the engine has been working for a number of miles, I think the head should be resurfaced, and the fitted back to the engine, with a brand new head gasket.
Before fitting the head, it is a good opportunity to check if no valve spring is broken, and maybe to change the valves' O rings.
As you will have to adjust the valves' gap your engine will run smoother.
Of course you must change oil, maybe twice (after let's say 50 miles) in order to clean the engine from this oil-water mess.
It happened to my good old 1992 Renault Clio which is still able to run up to 100 mph (when cops are sleeping )
Old 11-20-08, 06:44 PM
Thread Starter
Join Date: May 2007
Location: ga
Posts: 60
thank you alll for the help so far does any one know a place in the chattanooga area that could resurfaced the heads and do the heads realy need to be resrufaced when chaning the gaskets thank you
Old 11-21-08, 12:16 PM
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Join Date: Dec 2007
Location: Nashville
Posts: 635
Unhappy multiple problems

LOUD noises usually, but not always, spell trouble. Isolate the problem by manually operating the throttle while listening to the engine with the hood up. Does it increase/decrease with RPM? If so it is in the rotating mass of the engine or acc.. If it is is the engine(pistons, bearings_rods and mains_, oil or water pump, fllywheel, etc.), you will have to eliminate things one at a time. Does it start ok and idle? The smoke you mentioned is either steam(leaking head gasket or head probably) or brake fluid being sucked into the engine from the vacuum hose on the power brake booster( if you have power brakes). Oil burnes blue, to rich a mixture(fuel)will burn black, brake fluid will burn white.
A "tapping" noise, sounds like a lifter. Is the oil clean and when was the oil and filter changed last. Dirt in the oil will plug lifters and cause them to build up dirt and not operate properly. If it will run on 3 cyl.,I'm guessing it is a 4 banger, pulling off one wire at a time will tell you if you have a problem with a particular cyl.. More info will bring more results. Good Luck!

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