AboutCAJUNSC/RAMBLER390 Expertise 1998 and NEWER questions ONLY!! I WILL REJECT QUESTIONS FROM 1998 BACK. Electrical diagnosis. Brake Diagnosis. Driveability, Service Engine Soon Lights. Some Engine mechanical. Tires and wheels. ABS. HVAC. Air Bag (SIR). Interior, seats, etc... 6.6L Duramax Diesel diagnosis. 6.5L diesel diagnosis. I WILL not answer Alignment questions OR carburetor questions. No heavy internal transmission
I need YEAR, MAKE and MODEL of vehicle, and ENGINE SIZE and TRANSMISSION type, IF applicable to the question.
I work at a Large, Busy GM Dealership
Last thing, my answers are JUST SUGGESTIONS and ADVICE and you should ALWAYS CHECK with your mechanic for proper diagnosis and repair.
Experience 18 Years GM Dealership experience as an "A" line tech. ASE MasterTechnician. 100% GM paper certified and working towards MTC Certification.
Education/Credentials High School graduate. No College or higher learning.
Expert: CAJUNSC/RAMBLER390 Date: 1/5/2008 Subject: Follow-up question to another post
Question I have a 2003 Yukon with the 5.3 and need to replace the intake gasket due to hesitating and engine code for lean banks. I saw the other post with the procedure. The parts guy at the dealership said that the intakes often warp as well and are often replaced at the same time as the gasket. Do I need to worry about this and how do you determine if it is warped?
Answer Hi
After removal of manifold,
Use a straight edge for this procedure......
The intake plenum should also be checked for excessive warpage that may cause an uneven clamping pressure of the seal. If the plenum is found to be warped it will need to be replaced. Service Information states, "An intake manifold with warpage in excess of 3 mm (0.118 in) over a 200 mm (7.87 in) area should be replaced". Intake warpage is measured at the gasket sealing surfaces, and should be measured within a 200 mm (7.87 in) area. This measurement is across only two of the intake runner port openings. Measurements taken across the entire distance of all four intake runner ports will lead to unnecessary manifold replacements.
I have preformed this repair well over 50 times and have had only 1 manifold with a greater warpage than 3mm across 2 (TWO) ports ONLY. Not across the whole manifold.(4 ports).This is where ALOT of mistakes are made.
The one I did have was the first one I ever did, and it was obviously warped. (twisted).
Not saying yours MAY NOT be warped, but it is more UNCOMMON than common, at least here in the deep south.
This MAY not hold true in colder climates which I have no experience working in.
I do hope this helps
Please follow post back, if needed.
Good Luck
Pawl
