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2000 GMC Jimmy Intake leak

02-05-2011, 07:56 AM
I have a 2000 GMC Jimmy 4x4 4.3L that has a small intake leak couple questions for you guys

do the intakes go bad on these trucks or is it just the gaskets and should i replace the valve cover gaskets why im at it

do these trucks have a timing chain and do they ever need changed like the old belts used to

it has 85K so why im at it should i go ahead and do a tune up and if so what should it consist of and is it a good idea to clean the egr area

one last question is it ever a good idea to clean the injectors i have heard both good and bad about cleaning them with fuel injector cleaners

Thanks Jeff

02-05-2011, 10:59 AM
Lower intake manifold gaskets are a common problem on this engine. Felpro has an improved design gasket, (MS98002T). All gaskets, even rocker arm cover gaskets, are included. If the gasket is installed and torqued properly, it will not leak, period. There are articles in the Blazer "How-To" section that are very helpful.

Yes they have timing chains. I've got a couple 4.3's with over 300,000 miles and still have the original chain and gears. You can check for excessive slack, (chain stretch) by turning and measuring crankshaft rotation with a socket and ratchet. More than 12 degrees rotation, I'd think about replacing it. At 85K you shouldn't have any problems for quite a while.

Tune up: These engines are very fussy when it comes to tune up parts. All of these items are due at 100,000 miles: Spark plugs, distributor cap & rotor, use AC Delco only. Autolite Professional series spark plug wires are cheaper than AC Delco and have better specs. Air filter, fuel filter, Purolator makes good filters, (stay away from Fram). Both upstream oxygen sensors, Bosch are fine. Check fuel pressure and leakdown: the fuel pumps usually die around 100,000 miles, again, AC Delco or Delphi only.

Fuel injector cleaner: Not a bad idea. I've had good luck with Chevron Techron, and Lucas. Dump a bottle in every few of tanks of fuel. Most fuel already has injector cleaner in it, but adding more can't hurt.

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