kornellred

My 2007 HHR LS lost coolant temperature readings a couple of nights ago. The analog gauge was bottomed out and the DIC showed ---F.

According to what I have read, the ECM has a timer that measures how long it takes for the engine to warm up to normal operating temperature. If the thermostat is stuck open and the ambient air temp is low enough, the engine will take longer to reach normal temperature, and the timer in the ECM will time out and disable the AC and temp readings, and store a PO0128 trouble code. That is exactly what happened to my HHR. I have an OBDII scanner and I used it to clear the code. Now everything is fine.

I am going to replace the thermostat - chances are very good that it is actually stuck open. The night the reading stopped and the trouble code was set was a very cold one.

I went shopping for thermostats and found 4 different kinds, ranging from about $15.00 for a cheap no-name brand to $30.99 for an AC Delco OEM unit with 1 seal. The problem I am having is this: the two cheapies are described as having 4 seals. This makes no sense to me. The third model is described as being supplied with 1 seal - same as the AC Delco. The pictures for the first three show a flat round seal with a slit which stretches around the circumference of the t-stat body. The AC Delco t-stat is pictured with a bare metal circumference, with a separate low-res picture of the "seal" - which, in other literature, is said to be an O-Ring seal that the t-stat body sets against.

Should I spend the extra money and go with the more expensive AC Delco part?

Oh yeah - I am going to lose coolant when I change the thermostat. There is pretty clear evidence that Dex-Cool should not be mixed with green anti-freeze formulations. While researching this issue, I found out about a class action lawsuit against GM involving major engine repairs that traced back to corrosion issue with Dex-Cool. That was around 2002 to 2004 if I remember correctly. Is this a non-issue at this point it time?

Snoopy

Thermostat choice is up to you.....I USUALLY use OEM, but if you can't justify the price difference, I would probably use a name brand replacement, Stant comes to mind.

The law suit you speak off is old news on this forum and has been hashed around for as long as this forums existence. I use Dex Cool and believe in it. Off course, no mixing with others and always assure your coolant recovery is topped off. And I change it every 5 years.

Oh, and notice the law suit involved vehicles other than ours and OTHER THAN ALUMINUM BLOCKS.

I believe the law suit is now complete.

Grizzly old man

We bought our ‘06 HHR this last spring. The cooling system had already been flushed of the DEX coolant and a green coolant is in it now. I think its is Prestone.

From what I have learned all you really need to do is drain the DEX out flush the system a good one and put in something different. But,… DEX tends to clog things up so you might need to have the radiator and heater cooked out and put back in.

As far as replacing the thermostat goes, I do not particularly like OEM GM parts for such things. I used to have a body shop where my primary interest was buying repairable wreck vehicles and restoring the to useable condition and selling them.

I had a frame straightening machine and a bunch of other stuff for doing all this stuff.

Since most wrecked cars have front end damage I acquired equipment to fix radiators as well. I always like Daniel brand radiator things, not that it really matters but I think they are still made in the USA.

When I had the shop I would sometimes attempt a custom build and it was a lot of fun though I rarely made the money on a custom that I could on a regular complete stock rebuild.

Some fellows brought me a 72 Vega Camback that they had wedged a supercharged 454 with a and a 4 speed into. They had tunneled the back so the super big tires would swing and did a fairly decent job of that but where they had cut the hole for the Muncie transmission was mostly a big hole in the floor.

They had a top fill radiator sticking up about a foot over the D to try to cool the big mill. It was my job to build a cross flow radiator that would fit where the original tiny cross flow had been that could handle the job, and before it was over I had reinforced the floor and tinned in the big hole to cover the transmission. Then built some custom seat brackets so the original bucket seats would fit.

I lived in Wisconsin and the state required you to have a hood that covered most of the engine if you were planning to drive the car on the street, so I built one for them out of mostly wood and fiberglass.

About a month or so after the cold weather set in they brought the car back complaining that the heater had stopped working. I put the flo tester on it and it seemed like it had the coolant going through it at the right rate so just on a chance I pulled the thermostat. It was not only ‘open’ it was actually broken and could not close.

I poked a new 195 degree stat in and started the big block. In just a few minutes it was blowing heat like a good one.

843de

I'd stick with the Dex-Cool, there were issues at one time but they seem to have been dealt with. The important thing is to service the cooling system at the required intervals, change the coolant and flush the system when its called for and you wont have issues.

I use Stant thermostats and have never had a problem in 30 years of using them, if you want to go with the Delco part for peace of mind that's fine, but you shouldn't avoid quality aftermarket parts either.

Lucky

X2

hyperv6

I agree with Snop stick with Declo, Stant or Robert Shaw. When you buy no name it is a crap shoot as some are good and some are not.

The Dex Cool issue is very misunderstood. The issue was a few years back and it seemed that cars that had air in the system or too much water would become acidic. If you kept the Dex Cool at the right mixture and no air in the system it worked fine. They have changed the formula to be a little more forgiving and it should no longer be an issue.


Todays cars really have few things that are simple fixes like they used to be. Brakes, Stats, oil changes and even some Air Filters on some cars are so sensitive that if things are not done to the required standard it will set off a chain of issues.

The stat opening in the HHR so fast is to cut emissions. This is why the light comes on as it is not considered a emssions issue if it does not heat up fast. In the past they just let you freeze if it was stuck open and could care less.

So the new fast warm up system is a pain if it goes out but I do have to say in the winter it is nice to have heat in less than a mile.

Note too the Dex Cool class action was a joke. The lawyers just took it to court and no one other than them will see anything out of it. They do this as they know companies will settle as it is cheaper than fighting even if you are not at fault. Just a sign that our legal system needs some changes. But since most of the elected officals are lawyers we will never see it and just have to pay more money for products to pay these law suits.

I have had Dex Cool in 6 cars and have never had a hint of an issue. I do keep a watch on the system to make sure it is full and at the right mixture. My inlaws also have had 5 cars with Dex Cool and also nary a hint of an issue.

urbexHHR

There's nothing wrong with Dex-cool...just lack of maintenance. If Dex-cool was bad, you think they'd still be putting it in new cars?

sleeper

Dex-Cool here also... Why change to an antifreeze that requires more frequent changes ??

Not to mention if you ever had a warranty issue with cooling & the GM Tech saw Green instead of Orange.. S.O. L.

I have never had any issues in my vehicles that came stock with Dex-Cool..
Plus I make sure it is full, & replace as required..

843de

"Plus I make sure it is full, & replaced as required.."

Exactly, make sure you have enough of it and then change it when its due to be changed, you hit it on the nose sleeper.

BlackknighT

Obviously none of you have a 2000-2003 Chevy Impala with a 3.4.......