2000 Century, several symptoms

I’m not much for American cars, so I figured I’d toss it out to y’all. Friend just bought this car 3 weeks ago.

2000 Buick Century, 116k miles.

Temp gauge reads a bit warm, as high as 3/4 up the scale. She says it was starting to climb after she got off the highway and was in stop and go city traffic. OBD scan shows a high temp of 227 F idling in the driveway with both fans on. Turning on the HVAC with no AC lowers the temperature briefly, then the temp climbs again even when the heater is up full - and the heater works very well. Sometimes the temp will drop without doing anything. And sometimes the temp will drop even with the fans off. Air temp today is in the 50’s. I watched the temps for about 45 minutes. It never dropped below 200.

The car also intermittently shifts hard. Shutting it off and turning it back on makes this problem go away for awhile.

And it intermittently idles high. Blipping the throttle doesn’t stop this, but shutting it off and turning it back on does.

Coolant levels are good, coolant color is excellent (and it’s dexcool like it’s supposed to be). Transmission fluid is nice and pink. Oil was just changed about 500 miles ago.

The low coolant light came on shortly after she first got it, and the coolant was a bit low. No clue if it became low after she bought it, or if it was like that already. The radiator was full, but the overflow bottle was almost empty. I filled and bled about 2 weeks ago. It hasn’t lost coolant since, but until this past weekend the low coolant light stayed on. I saw from some research that the coolant sensor can get dirty and give a false low coolant reading. I do smell some antifreeze under the hood, but I don’t see anything spraying, and some did spray out when I bled it, so it could still be that burning off. I can’t detect any particular coolant smell around the radiator cap. All the hoses look good, the clamps are tight, and coolant is flowing through them.

Any thoughts?

The Buick Century is known for harsh shifting when it warms up. My in-laws 00 Century does this too. Lots of complaints but no true fixes. Has the thermostat been changed?

Haven’t done anything yet. Money’s tight for her so I wanted to do some diagnosin’ before throwing parts at it.

I had a similar probllem and it turnd out to be a clogged radiator. An IR temp gauge pointed at different areas of the radiator showed hot and cool spots. A new radiator fixed it. Couple that with a new rad cap and thermostat and it sjould be golden.

Good comments above. Quite of few posters here seem to like their Buick Century. I expect it is basically a good car. But it is 15 years old and has quite a few miles, so some problems are to be expected. It sounds like there are multiple issues here. For the coolant too hot problem, suggest to check if

  • the radiator cap is kaput
  • the thermostat is kaput
  • the radiator is clogged
  • the cooling system needs to be flushed, refilled, and bled
  • the sender unit for the dash temp gauge is kaput
  • the radiator fan isn’t turning on at the temp it should, or it isn’t spinning as fast as it should
  • the head gasket is starting to fail

Sometimes real life mimics OPs here. She now tells me that she’s been adding oil from time to time. I’d have loved to have known that before. She didn’t think the oil light coming on as she went around corners was a big deal.

I’ll have to do more testing this weekend when I have time, but I suspect @GeorgeSanJose 's first 4 suspicions are probably right. I’m seeing no evidence of oil in the coolant, or vice versa, so I’m hoping for her sake it’s not a head gasket.

I agree with above gentlemen, a clogged radiator is the classic cause of running hot under load, This car may have had little maintenance.

A thorough cooling system tune up is in order.

I hate to say it, but I think your friend will come to regret this purchase. There are too many red flags here, some of them big.

You may want to do a cylinder leakdown test, ,or at least a lab test to check the coolant for the presence of hydrocarbons, before suggesting any repairs to your friend. If there’s a headgasket that’s toast, and it’s been run this way, the cost to put it back in shape may not be worth it.

Post back with the results.

Gives me an excuse to buy a new toy anyway. Leakdown tester on its way! :wink:

I would buy a used brand name leakdown tester on ebay . . . versus a new harbor fake

Harbor Freight tools are fine.

“Harbor Freight tools are fine.”

That is relative

To what?

HF makes no claims or misrepresentations about their tools. They are what they are. And they’re affordable. If you need professional quality tools, as pros like yourself do, much of what they sell won’t do, but for the average guy working on his car they’re a great source of tools unavailable elsewhere. It would make no sense for the average Joe to have to buy shop quality equipment at industrial prices in order to do a job that he rarely does.

Just one example: I have a benchtop drill press at home from HF. It wouldn’t be of much use at all in the companies I worked in in industry. We needed equipment much more stable, much more precise, and much more durable with greater speed ranges and precise X,Y&Z coordinate adjustments and deep throats and depth capabilities. Precise location, precise depth, ability to use with soft materials as well as hard materials, ability to drill on large parts. But for my home use, it’s great. Those drills we had cost thousands, required riggers to install them, and needed footings in the concrete floor to keep them stable.

We had 500 ton presses. The 30T HF press can’t compare… but who needs a 500T press at home?

The point is that you can’t compare HF tools with industrial or professional quality tools sold to the trades. SnapOns are great, but way too expensive for the average buyer and unnecessary.

“If you need professional quality tools, as pros like yourself do, much of what they sell won’t do”

That pretty much sums it up right there . . . it’s okay for occasional home use

Some of it will stand up to sustained use, but much will not

I considered the HF one, because I’m not opposed to buying some of their stuff. Their brake caliper tool set works just as well as any other and didn’t require me to sell my cats to buy it.

But the reviews on their leakdown tester are horrible. I grabbed one off of Amazon. Did some research on it, and it appears to be a pretty good one - according to what I found, it’s the one that Matco rebadges, so I figure it’ll be OK for home use.

And the homeowner is their target market. Although I have to say that I’ve seen a fair number of shirts with company names embroidered on them. Independent contractors no doubt, guys just working for themselves.

“Harbor Freight tools are fine.”

That is relative

Funny thing happened today along those same lines. We had a customer waiting for a simple brake job that took longer than expected because we found the car needed brake hoses as well. The parts finally came in and I was helping another guy finish the job. I hung a caliper and just grabbed his Craftsman 3/8 flexhead ratchet. I tightened the bolts and said “how the hell do you get anything done with this piece of crap?” The head is so loose it just flops around and the gearing is so coarse that it makes it almost useless in all but a wide open space. Plus there’s a stupid button you have to push to remove your socket, making it impossible to do that with just one hand.

If that’s what a Craftsman tool feels like I can’t imagine what a Pittsburgh does.

It depends on what you buy there, I think. China stuff used to be synonymous with “crap” and a lot of it still is. After WWII (before my time), stuff coming from Japan was laughed at as poor-quality garbage. Over time, Japan evolved into an industrial powerhouse. Next up was Korea–same story. First stuff coming from Korea was pretty shoddy, now companies like Samsung and Hyundai make very high quality goods. I suspect China is on the way.

I still have a “doorbuster” el-cheapo cordless drill from HF that I bought at least 13 years ago. I abused the heck out of that thing and it still works fine. You can’t compare the quality or precision to a good Milwaukee or DeWalt, but it does its job. I too have a benchtop drill press from HF, and it serves my needs. I have one of their workbenches in my basement, and I’m impressed with the quality of it, at least for the price. Same with some other small power tools. When I needed a very small Torx driver to fix a cell phone, only 2 places had the size I needed. I could have paid $10 for one at a local tool house, instead got a whole set for $5 at HF.

The only things that I am wary about buying from HF are electrical items. Despite apparently meeting standards for sale in the US, a lot of their extension cords, power strips, etc. look a bit shoddy. I don’t mind if a cheap tool breaks, but I draw the line at something that might burn down my home.

And maybe it’s a guy thing, but you can’t walk by a HF “sidewalk sale” without stopping, and when that 20% off coupon arrives in the mail, plus a free multitester or flashlight (and who doesn’t need another of those to rattle around in their car), it’s pretty hard to not start looking for stuff to buy.