Rad fans go on when engine is cold

Hi folks
I have a 2001 Alero with a 3.4L. Lately, my coolant fans go on as soon as I start the car (AC is not on). This prevents the engine from running at the correct temperature. The idiot lights go on eventually and give a code for a failed themostat, but I don't believe this is the cause. If I clear the codes, the fans work properly for a few weeks, then they start going on prematurely again.

Another code it gave me was the oil pressure sensor, though I doubt it is related.

Also, there seems to be some lifter noise under load. Is this common on these engines? Do people just tend to leave it, or is it generally repaired?

thanks

Welcome to AF.

Check your fan relays, but it sounds like the temp sensor may be your problem. Here is a link for testing this.
http://www.automotiveforums.com/vbulletin/showthread.php?t=660655

I'd also inspect the wires to the temp sensor ,as they can become damaged and cause intermitant issues.

The ticking is usualy the lifters.
Oil burnoff causes build up , they can be cleaned up with some Seafoam engine treatment.
But you say it does it under a load, that could be the valves chattering. :eek:
How many miles, and do you change the oil frequently ?

Thanks for the advice

I just picked up the car and it has about 230,000 km on it. It appears to have been well maintained (inside of rocker covers is clean). It doesn't burn any oil and compression seems good.

I will try the coolant temp sensor test.

The engine tick seems to be rhythmic, but not really fast enough to be valve noise. It seems to tick for about half a second every 10 seconds or so.

p.s. is there a way to tell if the troublesome lower intake gasket has already been replaced? Does the gasket look different from the outside than the factory gasket?

thanks again