1994 toy pu rattle

toyota
pickup

#1

My son has a 1994 Toyota Pick Up, and it suddenly developed a rattle noise, but only when he is accelerating. I suggested he check for loose heat sheilds, or a broken engine mount, fan rubbing on radiator housing, but all of this is good. He had a new timing chain put in 30,000 miles ago, and a new clutch. It has 167,000 miles on it. The oil does not have flakes or coolant. It does not make the noise when not in gear and accelerating. could it be u-joints? He said is sounds like it is comming from the Lft Front, not the undercarriage. Fuel injected. does not overheat, or lug, or lack power. any ideas? 2wd. 5sd tranny.


#2

With the timing chain replacement, did it include a new tensioner and guides? If the tensioner or guides failed, the rattle could be the chain chewing on the side of the timing cover. This is bad, because it could easily wear a hole in a coolant passage, leaking coolant into the crankcase.

An easy check is to pull the valve cover and inspect the chain for tightness and inspect the guides.


#3

Ujoints would not be in the front left of the truck. I assume it is 2wd. A wheel bearing might cause a noise, goofing with the steering wheel while accelerating could be helpful. If the noise changes while steering left or right while accelerating could indicate wheel bearing. Failing motor mounts allowing the fan the hit the shroud would be my guess number 2. Does the rattle change consistantly with speed or engine rpm?


#4

The replacement did include all new gaskets and guides and gears as well. But your idea to check is a good one and I will pass it along to my son, thank you.


#5

I know the ujoints are back of the tranny, but it can be hard to isolate the source of a noise when driving and noise travels kind of like water from a leaky roof. It is 2wd. I doubt it is wheel bearings, cause it only happens when accelerating, not when decellerating or rolling at constant speed, and not when sittiing still out of gear. The noise once it starts is constant, does not change with speed of engine or vehicle. He checked the fan, the housing, the fan clutch, and all seem to be ok. the electrical is fine, no loss of power to the head lamps, and no loss of power to the engine. Fuel consumption has not changed, and it does not overheat. I still think it sounds most like a heat shield but I cant actually hear it as I am here in New Mexico, and he is in Calif. He just started a new job, is working 12 to 16 hour days, and that is why he asked me to come here and enquire about causes we have not thought of.


#6
  1. my son had part of his report wong. the noise does vary with engine speed. 2. I am at his place and I listened to the engine rev with the hood up. the noise turned out to be a cracked exhaust pipe about six inches down from the manifold. It cracked along the weld from the new catalytic converter, which was replaced about two years ago when some thief stole the one that was in it. I have advised him to drive with the window open, and get it fixed as soon as he has time, (he is working 12 to 16 hour days currently.

#7

Congrats on finding the problem and thanks for the follow up post.

As a temporary measure until he can get it fixed he can try using muffler patch on the crack to reduce the leakage. I used it on a cat converter once as a temporaty fix and it held up beautifully.


#8

thanks for the tip, I will get it done this weekend when he is off call.