Team-BHP - Wagon R Knocks!

No, it hasn't grown breasts, but the 20000kms driven 1.5 yrs old Wagon R I drive is knocking like crazy. Recently, the temperature is also going a bit above the usual 50% it hangs around. A phenomenon connected to this heating appears to be switching off of the AC. I didn't know cars did that, i.e. turn off compressor or something when the car heats beyond a certain point. But its happening.

I checked up the usual culprits - coolant and engine oil. Fanny also works when I switch on the AC. What could I be missing here?

P.S. Is it alright to put the coolant in the plastic bottle or should I send some directly by opening the radiator cap. The plastic bottle doesn't appear to be at a much higher level than the point at which it enters the radiator. Secondly, will the radiator "draw" fluid from the coolant reservoir when there's a shortage inside? Ideally, the pressure inside an overheated radiator would be higher and thus oppose incoming fluid, right? Wish I had paid more attention during the thermodynamics and fluid mechanics classes. :Frustrati

may or may not help but ..
1. Try resetting the ECU by disconnecting the battery for some 15 mins.

2. Also check if the battery grounding is Ok. In my Wagon the grounding wire was a bit tight and the battery guy warned me to get a new wire or else the car will start knocking if the wire snaps.

Its a good idea to inspect the radiator (not over flow tank) levels when car is cold.

Also see if the fan is working without AC also, both are separate circuits. It should come ON when engine temp shoots up and then run for around 1 min before it shuts down.

Another culprit can be your coolant thermostat relay which controls the flow of water.

Best is to get it checked, since overheating is not a good thing to ignore.

Check your radiator and AC heat exchanger next to the radiator, for choked dust. If your radiators are covered with dust, there could be heating problems. Give your radiators a good wash with a strong water pipe spray. Do this from both outside the front grill and from inside the bonnet. Take care not to splash water over the other electricals.

Quote:

Originally Posted by Jaggu

Its a good idea to inspect the radiator (not over flow tank) levels when car is cold.

..and top it up if there seems to be room?

Quote:

Originally Posted by Jaggu

Another culprit can be your coolant thermostat relay which controls the flow of water.

Any way I can check this?

What does the thermostat do and what typically... — Yahoo! Autos

Might be helpful.

Thermostat Checks

To check the thermostat, remove the radiator cap and start the engine while it is cold. Looking inside the radiator, you should see no movement of coolant. If you see movement, the thermostat is stuck open or is missing and repairs are required.

After the engine has run for five minutes or so, the upper radiator hose should start to feel hot signaling that the thermostat has opened and the coolant is now circulating through the system. Inside the radiator, you should also see coolant movement. If there is no movement (and the engine starts to overheat), the thermostat is defective and needs to be replaced.

A suspicious thermostat can also be tested by removing it from the engine and dropping it into a bucket of near boiling water. It should be closed when cold, then open once it hits the hot water, then close again after its been removed and allowed to cool. You can use a thermometer to check the exact opening and closing temperature.

Switching off AC is a cool functionality from the AC perspective, MSIL must have noticed it as defect in some place like cuddaph, where we had to manually do it with 800. Cars like Zen at that time would not heat up as they had a seperate fan and radiator for AC.

I know it is the silliest question to ask. Do you hear the radiator fan running ? Did you try running the car without AC?

Quote:

Originally Posted by arunmur (Post 826041)

I know it is the silliest question to ask. Do you hear the radiator fan running ? Did you try running the car without AC?

Firstly, how many fans are there in the Wagon R? I have spotted just one that comes on when the AC is switched on. It comes on with a loud hum, so I can hear it.

Yes, I have run the car without AC. What choice is there when the car overheats? Once the AC is switched off, the car returns to normal temperature.

I haven't noticed an increased load on the engine when the AC switches on either. So, I would rule out some jammed bearing in the compressor. Because of all this it is truly baffling.

Quote:

Originally Posted by Jaggu

What does the thermostat do and what typically... — Yahoo! Autos

Might be helpful.

Sure was helpful. But the thermostat seems to be working. The liquid is still with cold engine and starts bubbling after a little while of running.

Just have a check on the Hi-tension Spark-plug cables as well as the spark-plugs,might one of them loosing some current,second thing to check is the tapet head,may be the gasket is worn out and needed a relacement.

I'm facing the same problem in my Bro's Wagon R Lxi 2001 45k's on Odo.
The temp hangs around on the half way mark.

Knocking is happening when the accelerator pedal is more than half way down in any gear. Ambient Temperature is a bit high now around 40-42.
A/C on or off does't make any difference.

I tried removing the MPFI thingy box (to reset the ECU as mentioned in the thread)
Also checked battery connections and all the connections I could see in the engine bay.

When I took it the the Service guy, he calmly replied its pretty common now and the solution is the replace the "Radiator", I asked him can we do a flush ?
He said that will not help and said it it was something is the electronics as in the sensors the yellow light thingy for the MPFI will glow.
I asked about timing, he said that the timing could't be off.

He also mentioned I can drive the car as it is and will not cause any problem.

Help.......!please: