Questionmy father is one of those guys thats been working on cars for years so were do it yourself types, so we've already been down to the cam and everything and got nowhere so i appreciate the heads up on the lash adjuster and dealership thing and helpin us limit it down. is there anything i should worry about giving us trouble in the process? ie- timing belt or getting it in time or anything. this is our first go at a motor like this. lol
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so i bought a AT 91 mitsubushi 3000GT with the 3.0 dual overhead cam motor. at first, it had a bad miss to it but it had fouled plugs, so new platinums fixed that. now were dealing with a clicking noise near the top of the valve cover that gets worse as the RPM's go up. its in the area of the valve cover thats closest to the drivers seat. the engine is reading 190-200 on the compression check so i'm pulling my hair out. any suggestions or ideas would be GREATLY appresiated my man.
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Hi Slink,
I would say you have a bad tappet or lash adjuster as Mitsu calls it. It's a very cool little device the actually automatically adjusts your valves. It slides up and down but can get stuck if it gets dirty causing the valve to bottom out on it so you get a loud tap. It could also be starving for oil. Make sure your oil is full and clean. Check your oil pressure gauge inside on the dash. Unless you are a seasoned professional auto technician, this is not a repair for you. The lash adjuster is a precision device and if you were to pull it to clean it, you will need some clean diesel fuel to wash them in and a special tool. They are located under the cam shaft. Each side has two. Exhaust and intake. Book time calls for 5.9 hours with training. I could do this repair, but I'm getting to old. ;) I suggest you take it to your family mechanic and beg for mercy. Dealer will rape you on this repair. Probably $1500. No, there is no additive like STP that will help. Hopefully, you low on oil. This would indicate that you may have a leak and topping it off might make this go away. Let me know how this turns out!
AnswerFor some reason they used a belt instead of a chain for timing. So I would look at that while your there and of course the tensioner. I would replace both before it's too late. Unless you know it's been done before. Plug wires, that's a no brainer. Air filter, fuel filter. Stuff like that. Ah, I found a TSB on this tick noise and it refers to the lash thingies. Here is the text, I can't send pics, but you should be able to look this up on-line.
NO.: TSB-95-11-001
DATE: November, 1995
MODEL: V6 and DOHC Models
SUBJECT:
VALVE NOISE AT START-UP
BACKGROUND INFORMATION
On V6 and DOHC models, it is normal to hear a valve noise (a "ticking" sound) during the first two minutes after engine start-up. However, vehicles that are overdue for oil change or have not been started for a long period of time may experience the noise for longer than two minutes. The noise is caused by air in the high pressure chamber inside the automatic valve lash adjusters.
Replacing valve lash adjusters will probably not eliminate valve noise. This bulletin contains procedures to bleed air out of the adjusters and to confirm that the adjusters do not require replacement.
NOTE : For Eclipse models with 420A engine, refer to the "Lash Adjuster Check" on page 110-12 in the 1996 Eclipse service manual. Do not perform the procedures in this bulletin.
VEHICLES AFFECTED
All V6 and DOHC models
PROCEDURE
If valve noise (a "ticking" sound) lasts more than two minutes after engine start-up, perform the following steps in order:
1. Check the engine oil level and quality, and correct as necessary. Start the engine. If the valve noise continues for longer than two minutes after start-up, continue with Step 2.
2. Warm the engine to normal operating temperature. Increase idle speed gradually to 3,000 rpm, then back down to normal idle speed. Repeat this process several times (maximum of ten times). If the valve noise continues, stop the engine. Inspect the automatic valve lash adjusters as described in Steps 3 and 4 below.
CAUTION : Wear protective gloves and use care to protect yourself from hot engine components.
3. Remove the oil cap on the rocker cover and listen for the source of the noise. If it seems to be coming from the valve lash adjusters, proceed to Step 4. Otherwise, refer to section 11 of the appropriate service manual for further engine diagnosis to determine the cause of the noise.
4. Remove the rocker cover.
5. Using finger pressure, push down on the rocker arm over the head of each valve lash adjuster.
NOTE : Be sure that the camshaft lobe is on the flat side when performing this step.
a. If the head of the adjuster sinks when finger pressure is applied, the adjuster must be replaced.
b. If the head of the adjuster stays firm when finger pressure is applied, the adjuster is operating normally. Do not replace the adjuster. Refer to section 11 of the appropriate service manual for further engine diagnosis to determine the cause of the noise.
WARRANTY INFORMATION
Valve Lash Adjuster Inspection (All)
Nature Code: 80B Cause Code: 220
Labor Operation Number: 11321500 Time Allowance: 0.3 hrs.
Warranty Coverage:
36 months/36,000 miles if not related to owner maintenance.
Special Warranty Information:
^ Use labor operation number 11131000 for rocker cover removal and reinstallation. (0.2 hrs. per cover, i.e., V6 = 0.4 hrs., 4 cylinder = 0.2 hrs.)
^ Perform only when due to customer complaint and after attempt to determine if due to lack of maintenance (i.e., overdue oil changes). If due to lack of maintenance, advise customer that condition is their responsibility. Advise customer that a ticking noise for a short time during warm-up is normal.
