HHR FAN JUST NOT CUTTING IT (Stock 318)

[TRIPLE-GREEN]

A few months ago I pulled out the stock fan on my 73 challenger and installed under great recommendation a Chevrolet HHR electric fan. It went in great and I installed a 175 thermostat into the radiator port. The radiator is about 2-3 years old but honestly the car has never overheated before. I just wanted the horse gain. I converted the car to a high amp alternator to make sure the fan had plenty of juice. Although I feel that the fan comes on a little late it just can not keep up with longer drives. I have now over heated the car 2-3 times. I'm about to trash the fan and move back to a pully driven fan. I wanted to check here first.

The car has a stock 318 with a stock style brass radiator, 4brl intake and new TTI exhaust. The fan runs good and strong but when I drive it more then say 30 miles on a standard or high heat day the temp gauge goes half way up and climbing. If I pull off and let it idle for a while it comes down a little but is much higher then it has ever been in the past.
  Ideas on what I can do? I have heard people here using them on much larger motors with no trouble. So that is why I am like WTF? 

[Chryco Psycho]

do you have vacuum advance connected & what to , if it is on manifld vacuum disconnect it

[brads70]

strange? I have it on my 440/727 and it works great. Drove it 800 miles to and from Carlisle with no issues till we got stuck at a border crossing for about an hour and a half. The first hour was no problem but then we got stuck up beside a big wall with no airflow around and it was REALLY hot outside like over 90F and REALLY humid! We had to pour a few water bottles over the rad to keep it under 200F.
I have an aluminum rad though ( a compared to your set up?) I changed the sensor so it comes on earlier after I got back from Carlisle. Around town it only comes on when your stopped in traffic, other wise the fan is off most of the time.
Sheesh don't know what to suggest ...?

[the_engineers]

Have you had any work done to the radiator? How old is the water pump?

[burdar]

If it is getting hot while cruising down the highway, make sure you have a spring in the lower radiator hose.  The water pump can suck the lower hose shut on the highway causing the engine to overheat.  A spring in the hose doesn't  allow it to colapse.

[TRIPLE-GREEN]

Have you had any work done to the radiator? How old is the water pump?

The water pump is getting old, but the radiator has not been trouched since it was put in 2 years ago. It was a stock replacement radiator.

I didn't even think about the radiator hose closing up.

I have a vaccume advance off of the edelbrock carb.

[Strawdawg]

  with Burdar.  If it gets hot on the road, then it is not the fan.  It should run fine without a fan on the road once you are over about 40 mph

[TRIPLE-GREEN]

I can totally see where you are coming from with the hose thing, but why would it start doing this only after the electric fan was installed? I ran this car as a daily driver 15 miles both ways for 3 years and it never so much as got to warm. Then I put in this electric fan and fooie.

[BB73Challenger]

Like said on the freeway you would be pushing more air than any fan would pull or push through... how about that t-stat?
If these are the ONLY 2 things you changed I would be putting a little thought that way too.

Also if you are concerned about the fans ability make sure you can have a piece of paper hold itself up to the rad to make sure it is pulling enough air. What's the odds that maybe it's running the wrong direction? Just thinking out loud and trying to throw some ideas out there.

[burdar]

I've heard of some electric fans restricting airflow.  I'm not saying that's what is happening here...just trying to give you some ideas.

[Cooter]

Personally, the ONLY TIME I run anything electric fan is when room is at a premium..Other than that, i run the OEM Clutch style fans with shroud.

[TRIPLE-GREEN]

I went home last night and had a good look over the car. Honestly I can squeeze the lower radiator hose shut with very little effort. So I think the hose issue might just be a good lead. The fan feels like it is pushing out a massive gust of air. Honestly it's blowin more hot air then my wife  . I will look into changing my hoses and see if that helps.

The thermostat is only about a year or so old. Just replaced it when I had the 4brl intake put on.

[Chryco Psycho]

if you cannot locate or buy a new hose with a spring inside you can coil up a couple of steel coat hangers to keep the hose open

[422STROKER]

Maybe verify the temp with a non contact temp gun?  Could be a sending unit issue?  Is it puking coolant out?

Tom

Hows the engine tune?

FWIW it shouldn't be sucking the hose closed at idle or low rpm driving.

[TRIPLE-GREEN]

Maybe verify the temp with a non contact temp gun?  Could be a sending unit issue?  Is it puking coolant out?

Tom

Hows the engine tune?

FWIW it shouldn't be sucking the hose closed at idle or low rpm driving.

I have a bottle on it but when I stopped it and checked to make sure the fan was still running I didn't hear it spitting up anything. everything seemed to be running like normal. Haven't had a chance to change the hose yet. But will keep you guys posted. Thank you all so much for your help.