My 99 XJR just started making a noise in this cold weather that has me perplexed. When I turn the key to the run position, I hear a sound that can best be described as similar to a power antenna type noise. This sound seems to be coming from the front right side of the engine. The noise continues when the car is started and running.

Is there some kind of electric motor or pump that could be making this noise?

 

Could be the blower for the cabin heater depending on how you have the climate controls set.

 

I still hear the noise with the climate control turned off. I lifted the hood, and the noise seems to be near the front of the right hand cam cover, or maybe near the pulleys. I can't quite pinpoint it. It's loudest near the front of the engine, and louder on the passenger side than it is on the driver side. It sounds like some kind of electric motor running (almost like a power antenna or fuel pump). The sound occurs whenever the key is in the run position, whether the car is running or not. The sound stays the same, regardless of RPM.

It seems like the colder the outside temperature, the louder the noise gets. It's not as loud today as it was yesterday or the day before.

 

It's your intercooler water pump, I'd say. It lives on the right side frame rail by the radiator.

It's on the frame aft of the rad, and it's a black plastic cylinder with two small hoses on it.

Mine is not noisy, I can hear it if I go looking, but yours must be dying. Check your coolant level and make sure there's no air in the system.

 

Thanks. I'll check it out. Is that an electronic pump?

 

Yes it is electric, and here it is.

 

Thanks. I'm sure that is where the noise is coming from. Is it much of a job to replace it?

 

I don't know, but it doesn't look too bad. You have to follow the bleed procedure to make sure all the air is out, otherwise the pump just cavitates.

 

What would be the consequences of a complete failure of the intercooler pump? Will it damage the supercharger?

Please pardon my ignorance, but this is only the second supercharged car I've owned and is the only intercooled car I've owned. I still have a lot to learn.

 

Probably the only thing is a loss of horsepower. The intercoolers are there to cool down the air after it comes out of the supercharger, because cool air is more dense and produces more power.

 

That's good to know. As long as I don't have to worry about a breakdown, I can deal with a loss of power until I can replace the pump next month.

 

in this weather your problem is more likely getting enough heat into the cabin

 

No doubt... lol. Plenty of heat, but the fan doesn't push the air hard enough.