Timing belt replacement?

GIO2111

MEMBER
1999 NISSAN PATHFINDER
V6
2WD
AUTOMATIC
160,000 MILES

I was preparing to change the timing belt and had all my cam sprockets (left and right) and crankshaft marks set at TDC. While attempting to loosen the right cam sprocket attachment bolt to check the cam seal (the cam seal appears to be leaking) and with the timing belt removed. The right cam rotated independently counterclockwise about a quarter of a rotation. I attempted to reposition it back to TDC by rotating it clockwise back to the timing mark, but it skipped forward about a quarter of a turn and I heard a "thump) in the engine. I then rotated counterclockwise back to the TDC mark. All marks are again lined up at TDC. The left cam sprocket (the one without the leaky seal) and the crankshaft never moved.

My question is, did the rotation and thump mean there is a problem (bent valves etc)?
Now that everything is lined up again can I be confident everything is in the correct time again.

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Sunday, November 30th, 2014 AT 7:30 PM

16 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

I attached the timing marks for you to view for the repair. After you install the tensioner, make sure the marks are exactly lined up. A lot of times the gears move when you apply tension. If it does then it has to be reset.

https://www.2carpros.com/articles/how-a-timing-belt-works

I would check the compression before you start it as well. I remove all the spark plugs for this repair anyway so the parts turn easily.

https://www.2carpros.com/articles/how-to-test-engine-compression

I also attached below a YouTube video of the repair for you to follow. It is a great video.

https://www.youtube.com/watch?v=eDVq7B6zIAw

Roy

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Saturday, November 21st, 2020 AT 8:14 AM

TONYMAC

MEMBER
2 POSTS
1994 NISSAN PATHFINDER
198,563 MILES

I had to replaced the timing belt on my 3.0L V6 and I set the belt to the correct marks on the block and the timing belt to the ones on the crank and camshafts. It has a hard time starting now and I have done everything by the book. If it does start it runs rough for a few seconds and then low idle dies. I cant keep it running. It is getting enough fuel, sometimes too much, and it barely has any compression in the 1, 3 and number 5 cylinders, but once started it has proper amount of compression. Please help.

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

RASMATAZ

MECHANIC
75,992 POSTS

Best verify if the valve and ignition timing is correct-Did you put engine no.1 piston on is compression stroke/TDC

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

TONYMAC

MEMBER
2 POSTS

Yes I have. I have tried it 180 out and 180 in and still it starts dies and then wont start again until a few minutes later. Besides checking for spark, which I am doing in the morning, what else can I do?

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

RASMATAZ

MECHANIC
75,992 POSTS

Check and test the IACV/AAC valve and fuel pressure if its within specs

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

ROB SHARPE

MEMBER
1 POST
1993 NISSAN PATHFINDER
6 CYL
4WD
MANUAL
127,000 MILES

Have a 1993 Nissan Pathfinder with a VG30E engine. The timing belt broke and I am sure that the crankshaft has moved without the camshafts moving. The shop manual states that the valves maybe bent if this happens.
Two questions.
#1 Is there a way to tell if the valves are bent without pulling the heads?
#2 to install a new belt what is the procedure to align the crankshaft with the two over head camshafts to get the engine back into sync?

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there.

You will have bent valves, even if the engine was at idle speed, you will bend valves when a timing belt brakes on this engine.

Mark (mhpautos)

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

ROBERT ERWIN

MEMBER
18 POSTS

Will you hear any noise when this belt breaks?

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

KEN L

MASTER CERTIFIED MECHANIC
47,347 POSTS

Not really the engine will just stop running. Did this happen to you? Here is a guide to help you replace the timing belt:

https://www.2carpros.com/diagrams/nissan/pathfinder/1993

Please run down this guide and report back.

Cheers, Ken

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

SCOTTSCOTT07

MEMBER
21 POSTS
1991 NISSAN PATHFINDER
100,000 MILES

I am not sure what is wrong but I drove my truck home one night and the next morning I wake up to start it and it wont start and makes a different noise then it usually does, kinda like its going to fast and my tac gauge moves if I give it gas the tac will shoot up to 4 or 5 and then drops back down I can also hear a weird ticking in the engine when I stop trying to start it. I did a spark test and there was no spark so I did a whole tune up (it needed it anyways) and got a new ignition coil but this did nothing the same things are happening and it still wont start. I was told it could be my distributor or my timing belt but im not sure and I dont know what else it could be any help would be much appreciated

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

ASEMASTER6371

MECHANIC
52,797 POSTS

I attached the procedure for the replacement of the timing belt for you.

https://www.2carpros.com/articles/how-a-timing-belt-works

There is a procedure below and some pictures attached.

I also posted a youtube video for you as well.

https://www.youtube.com/watch?v=CvMaBZXgSkA

Roy

CAUTION:
Do not bend or twist timing belt.
After removing timing belt, do not turn crankshaft and camshaft separately because valves will strike piston heads.
Make sure that timing belt, camshaft sprocket, crankshaft sprocket and belt tensioner are clean and free from oil and water.
Installation should be carried out when engine is cold.

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REMOVAL
1. Remove engine under cover.
2. Drain engine coolant from radiator.

NOTE: Be careful not to spill coolant on drive belts.

3. Remove radiator.

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4. Remove engine cooling fan and water pump pulley.
5. Remove the following belts.
Power steering pump drive belt
Compressor drive belt
Alternator drive belt

7. Remove distributor protector.
6. Remove all spark plugs.
8. Remove compressor drive belt idler bracket.
9. Remove fresh-air intake tube for rocker cover.
10. Remove water hose for thermostat housing.
11. Remove crankshaft pulley bolt.
12. Remove crankshaft pulley with a suitable puller.
13. Remove upper and lower front belt covers.

Timing Belt Alignment Marks
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14. Set No. 1 piston at T.D.C. on its compression stroke by rotating crankshaft.
a Align punchmark on L.H. camshaft sprocket with punchmark on timing belt upper rear cover.
b Align punchmark on crankshaft sprocket with notch on oil pump housing.
c Temporarily install crank pulley bolt on crankshaft so that crankshaft can be rotated.

Loosening Tensioner Pulley
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15. Loosen timing belt tensioner nut, turn tensioner, then remove timing belt.

INSTALLATION

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1. Confirm that No.1 piston is set at T.D.C. on its compression stroke.

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2. Install tensioner and tensioner spring.

NOTE: If stud is once removed, apply locking sealant to threads of stud on cylinder block side before installing.

Retracting Spring Tensioner
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3. Turn tensioner fully outward with hexagon wrench and temporarily tighten lock nut.

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4. Set timing belt.

Timing Belt Alignment Marks
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(1)Align white lines on timing belt with punchmarks on camshaft sprockets and crankshaft sprocket.
(2)Point arrow on timing belt toward front belt cover.

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(3)Number of teeth.

5. Loosen tensioner lock nut, keeping tensioner steady with hexagon wrench.

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6. Turn tensioner 70 to 80 degrees clockwise with hexagon wrench, and temporarily tighten lock nut.
7. Turn crankshaft clockwise at least 2 times then slowly set No.1 piston at T.D.C. on its compression stroke.

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8. Push middle of timing belt between R.H. camshaft sprocket and tensioner pulley with force of 98 N (10 kg, 22 lbs.).
9. Loosen tensioner lock nut keeping tensioner steady with hexagon wrench.

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10. Set feeler gauge as shown in figure which is 0.35 mm (0.0138 in.) thick and 12.7 mm (0.500 in.) wide.

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

DOPEYD697869

MEMBER
1 POST
1990 NISSAN PATHFINDER
6 CYL
4WD
AUTOMATIC
245,438 MILES

Timing belt broke, replacing it and cannot get cams and crank in time together.

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

FISHERDEAN6

MEMBER
1 POST

Done one about 18 months ago, hard to find timing marks on the block and in the Haymes manual, but when you find them, it all fits easy, if you've got the right book, piece of cake

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

MHPAUTOS

MECHANIC
31,937 POSTS

A broken timing belt will bend valves, this is an interference engine, the heads will have to come off, see pic for warning on Mitchel 1.

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

WHITANDERS

MEMBER
1 POST
1990 NISSAN PATHFINDER

I am changing my timing belt on a 1990 nissan pathfinder. My aligning mark at the bottom seems to be straight down and the mark on the belt matches it but in all the diagrams it is at about 5:00. Not sure which position I should use.

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Saturday, November 21st, 2020 AT 8:17 AM (Merged)

RASMATAZ

MECHANIC
75,992 POSTS

Ensure No. 1 piston is at TDC of compression stroke. Remove valve covers and loosen all rocker arm shaft bolts. DO NOT bend timing belt.
Install tensioner and return spring. If return spring stud has been removed, apply thread lock sealant and reinstall. Turn tensioner clockwise and temporarily tighten lock nut. Install timing belt. Align White lines on timing belt with punch mark on camshaft sprockets and crankshaft sprocket.
Arrow on timing belt must be pointing toward timing belt front covers. There should be 40 teeth between the left camshaft and right camshaft aligning marks. See Fig. 9. There should be 43 teeth between the left camshaft and crankshaft aligning marks.
Loosen tensioner lock nut using Allen wrench, slowly turn tensioner clockwise 70 to 80 degrees and temporarily tighten lock nut. Turn crankshaft clockwise 2 or 3 times.
Return to TDC of compression stroke. When camshafts and crankshaft marks are aligned, tighten tensioner lock nut. Refer to TORQUE SPECIFICATIONS table. Ensure No. 1 camshaft lobes are not lifting valves. Tighten rocker arm shaft bolts in 2 steps. See TORQUE SPECIFICATIONS table. To complete installation, reverse removal procedures.

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