Supra 89 Turbo Knocking

[mohan]

I have a toyota supra turbo 1989 model.

1. The engine was changed by the previous owner two years back. The engine gives a knocking vibration when the car is standstill with engine running normally. (At standstill the engine runs at about 1000 - 1200 rpm in neutral/parking position).

On a different note, the car gives a slight jolt at the final moment of braking even if the braking is slow and steady. The braking is not smooth although the braking is very good. The pads are new.

The mechanic says both the symptoms are interrelated and is due to bad front suspension. Can someone kindly help with ideas?

2. The automatic transmission oil needs topping up every week. Oil seems to be present on the bracket that holds the oil container itself. Any ideas please?

3. The radiator has to be topped up with about a litre of water every week. Is that normal? There are no obvious signs of head gsket problems (white vapour from exhaust or deposits on the inside of oil cap).

Thanks in advance.

[mrnickleye]

You should go to several shops for a 'free' opinion about the knocking sound.

I doubt that any bad front end components will knock at a stand still idle.

The transmission may have a leak at the front seal. Look under car for drips at the bottom of the bell housing at front of trans....at the pan gasket on bottom in middle of trans....and at the tail housing seal where drive shaft yoke goes into trans.

The coolant is going somewhere, either out on the ground, or into the engine. Looks closely for leaks outside motor. These cars are known to blow head gaskets. A shop can perform a pressure test for leaks outside, and a block test for internal. Only takes 10 minutes for both tests. My leak did not get bad enough to get white smoke from the tailpipe. When I tore it down, I easily found the bad area on the gasket.

Don't bother with those 'stop leaks' in a can. They won't work on this motor.

I am a manager at a repair shop, and ASE Master Technician for 20 years.

[Mick24]

I go along with the Head Gasket theory - they tend to fail around the water jacket on No.6 Cylinder,and you normally end up skimming the cylinder head also.

If the engine has done more than 70,000 miles,it would benefit from a de-coke as well.

[Karma Supra]

I have a toyota supra turbo 1989 model.

1. The engine was changed by the previous owner two years back. The engine gives a knocking vibration when the car is standstill with engine running normally. (At standstill the engine runs at about 1000 - 1200 rpm in neutral/parking position). Can you see it "wobbling" in the engine bay? does it move lots when revved? Is the engine idling at that speed when hot?? Is it misfiring?

On a different note, the car gives a slight jolt at the final moment of braking even if the braking is slow and steady. The braking is not smooth although the braking is very good. The pads are new. Not entire sure what you mean by a slight jolt, does the braking suddenly get firmer? do you experiance any suspension knocks over bumps?

The mechanic says both the symptoms are interrelated and is due to bad front suspension.  Can someone kindly help with ideas? I'd say thats a load of bolleaux.. but I have not seen it.....

2. The automatic transmission oil needs topping up every week. Oil seems to be present on the bracket that holds the oil container itself. Any ideas please? Not sure what you mean by the oil container, is it to the right left of the engine, near the front? if so thats the power steering fluid resevoir, check the lines and where the pipes connect to the pump, resvoir, etc. no supra I have seen has a seperate oil container for the transmission!

3. The radiator has to be topped up with about a litre of water every week. Is that normal? There are no obvious signs of head gsket problems (white vapour from exhaust or deposits on the inside of oil cap). Not normal at all! mine has not moved in 6000 miles. Check the top hose that goes from the back of the head to the heater matrix, in not that check the over flow bottle, is water being ppushed into that? in not that check under the car if it is weeping out of the rad drain pipe (bottom right of rad)

Thanks in advance.

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[mohan]

I have a toyota supra turbo 1989 model.

Thanks to all for the suggestions.

1. Can you see it "wobbling" in the engine bay? does it move lots when revved? Is the engine idling at that speed when hot?? Is it misfiring?

When in neutral/parking with the engine running, it gives a knock ( a sort of light wobble - something like a sudden stopping of engine in a manual transmission car) every five or six seconds. One of the mechanics I took it to a few months back said it is due to wrong 'timing'.

Not entire sure what you mean by a slight jolt, does the braking suddenly get firmer? do you experiance any suspension knocks over bumps?

I have not experienced any suspension knocks over bumps. It is normally like a firm suspension on the bumps. The braking as you said gets firm at the last moment as if I applied a sudden brake. Although, I would like to add that the braking does start normally but gives a little forward push to the body (as if due to inertia) at the final moment.

Not sure what you mean by the oil container, is it to the right left of the engine, near the front? if so thats the power steering fluid resevoir, check the lines and where the pipes connect to the pump, resvoir, etc. no supra I have seen has a seperate oil container for the transmission!

Yes, it is the Power Steering reservoir! I find oil in the minute gap between the reservoir and the clamp holding it. Ofcourse the oil trickles down and hence when seen from the bottom of the bonnet, there is oil on the various parts below the reservoir.

3. Not normal at all! mine has not moved in 6000 miles. Check the top hose that goes from the back of the head to the heater matrix, in not that check the over flow bottle, is water being ppushed into that? in not that check under the car if it is weeping out of the rad drain pipe (bottom right of rad)

There is no leakage from the drain pipe. When the engine is hot, the water used to be pushed into the overflow bottle. However, I have not observed this after a put in a new radiator. Will need to have a look. Also need to check the top hose as suggested.

Thanks once again to all.