G'Day guys, I as rewiring my trailer hitch on my 1980 240 GL today and all was good till the battery went flat, doh! I jump started it and finished my wiring and left the car idling for 30-40mins whilst i did so. Finished up and thought i should go for a spin to charge the battery. I made it about 150M and the motor started spluttering and wouldn't idle. A whole bunch of whinning high-pitched horrible noises but I gave it a few revs and all was good. Wanr for about another 30mins on the freeway and it was running great and when I was at the lights it idled great. However, on the way back as i came off the motor way the crazy noise started again. I made it home OK and the motor appeared to run fine but the noise was coming from the under car pump. I only had the in-tank pump replaced about 3 months ago when it was making this noise last time and it has been fine sinse. I could swear I also heard a noise from under the bonnet when this happened bu it is hard to tell when these noises travel. In-tank pump is working as i can hear it, what could this possibly be? Maybe the under car pump or something else? Any pinters would be greatly appreciated as it only came back from a service a week ago and they stung me nearly $700

How long since filter changed? When they start to get plugged the main pump works hard and will get warm and make noise.

If the hose connecting in-tank pump to discharge pipe wasn't installed properly and failed the main pump will suck air and whine about it, fill fuel tank to full to check this.

Some main pumps are inherently noisy but seldom fail.

Gday mate. Blew the filter out about 2 weeks ago, pretty filthy but ran much better for it. The tank is down below half full so i guess a simple test would be ti fill it up. Would it be fair to say thet if the noise goes away on a full tank and only appears on less than half a tank it has something to do with the in-tank pump? Man I'll be pissed with the guys wo replaced the in-tank pump 3 months ago! I did check the old rubber hose on my old in-tank pump and although the outer rubber had a couple of cracks it was still keeping a good seal should they have ecided to re-use it. Curiously I went out to the car last night and started it up and no noise at all...... Will run down to the shops in a minute and see if it is still noisy.

You need to find out where the noises are coming from. If it is under the bonnet are the alternator, water pump, and A/C compressor turning free? If the fuel pump was making the noise it seems unlikely it would stop. Was the rubber hose replaced in the tank when the intank pump was replaced. Dan

How long since you adjusted the alternator belt, and cleaned the battery terminals?

Gday mate. New belts last service and battery terminals OK. Would this have an effect on the fuel pump?

Weak alternator output has a direct affect on all electrical components.

Bill