Timing Chain Rattling Noise On 1999-2002
Suzuki 2.5L H25 Engines
The AERA Technical Committee offers the following information regarding a timing
chain rattling noise on 1999-2002 Suzuki 2.5L & 2.7L engines. This noise comes from the
front of the engine, behind the timing cover, and is normally heard the loudest when the
engine is cold. Vehicles affected are the Grand Vitara & XL-7.
There are three timing chain tensioners on this engine, and causing this problem is the
number 1 timing chain tensioner that is not properly adjusted. In order to fix the problem,
Suzuki recommends replacement of the number 1 tensioner only.
If there is a tensioner noise for the first 5 seconds of engine operation, Suzuki considers this acceptable under
normal engine operation.
Apply sealant “B” Suzuki Bond 1207B (Part #991104-31140) to the timing cover mating surface of the cylinder
block and head. Use a plastic scraper as a jig to force the sealer into the air gap formed
between the cylinder block, head and head gasket.
NOTE: Failure to perform this step will result in an oil seepage that will migrate down the front
of the block and be diagnosed as a crankshaft seal leak.This is not a job for the average owner to undertake. Unless you are an experienced Tech with the correct tools and shop manual, the chances of something going very wrong are possible.
The flat rate on this job is 8.3 hours and requires the front of the engine to be removed. If you know what you are doing, you can remove the timing cover without having to pull the front diff and remove the oil pan, intake manifold and valve covers.
The engine is an interference fit, so being 1 tooth off on the timing can (will) bend valves.
In my experience, if the tensioner is gone, then the chain, sprockets and guides will also be worn and should be replaced as an assembly.
I would strongly recommend having the dealer do this repair. I've watched experience 'Zuki mechanics get sidetracked and have to pull the heads to fix the screwup. 3 times in 3 years by guys that do them everyday.
In Canada, Suzuki has found that replacing just the tensioner is not effective in the long run. They have revised the bulliten to include the replacement of the chain and sprockets if there is any signs of wear. When you get the cover off, check how far the tensioner has extended, if it's more then about 4-6 clicks, the chain is stretched and should be replaced.
Idler sprocket 45 N.m
(4.5 kg-m, 32.5 lb-ft)
Timing Chain Tensioner Nut Tightening Torque
27 N.m (2.7 kg-m, 19.5 lb-ft)
Timing Chain Tensioner Adjuster Bolt Tightening Torque
11 N.m (1,1 kg-m, 7,5 lb-ft)
Timing Chain Guide Bolt Tightening Torque
9 N.m (0.9 kg-m, 6.5 lb-ft)
Timing Chain Guide #4 Bolt Tightening Torque
11 N.m (1.1 kg-m, 7.5 lb-ft)
Timing cover bolts
11 N.m (1,1 kg-m, 7,5 lb-ft)
150 N.m (15 kg-m, 108.5 lb-ft)
Here is a quick rundown of how to change the tensioner only. If upon inspection the chain, and sprockets need replacing the valve covers need to be removed not just lifted. This involves removing the intake manifold so the valve covers can come off. I plan on putting together a document with photos for others wanting to do this themselves. The torque specs are in this thread so I wont repeat them but will put them in the next version.
1) First thing is to disconnect the battery.
2) Drain coolant from petcock at bottom of radiator.
3) Disconnect transmission lines from radiator, put something in lines to plug (I used a large bolt).
4) Disconnect power steering reservoir from radiator (two bolts)
5) Disconnect coolant hoses from radiator
6) Loosen belts
7) Remove 4 bolts holding fan in place
Remove 2 bolts holding in radiator
9) Remove radiator, shroud and fan at same time (do not remove shroud from radiator)
10) Remove belts
11) Remove tensioner pulley for P/S pump and A/C compressor (2 bolts)
12) Remove P/S pump from bracket (2 bolts accessible through holes in pulley)
13) Remove P/S pump bracket (3 bolts)
14) Remove harmonic balancer (use of impact and puller are necessary for this step)
15) Remove 2 front nuts and loosen 2 rear nuts on both valve covers
16) Loosen valve covers (I used a dead blow hammer for this)
17) Place a wood shim between valve cover and head to lift valve cover off top of timing chain cover
18) Remove bolts holding timing cover on (about 30 bolts, 4 come up from the front of the oil pan
19) Tie the timing chain in place. You do not want it to move when you remove the tensioner ( I used welding wire to tie the chain)
20) Remove old tensioner
21) Install new tensioner then remove tie wire
22) Clean all mating surfaces of grease, oil, and old gasket material
23) Apply new gasket material pay close attention to areas where the head meets block, head meets valve cover and block meets oil pan
24) Reassemble in reverse order