That has been a good car for her. I bought it for her when she was in high school used and she is still driving it 7 years later. If you have the buick 3.8, it's a great engine, lots of power. But they had problems with the intake gaskets leaking coolant, I had to change hers out.

They also have problems with the transmissions those few years. There is a valve that modulates the pressure to the lock-up clutch in the torque converter. The bore that this valve works in wears out, and it messes up the torque convertor clutch, pulling a hill in overdrive you will get a shudder, it feels like the engine has a miss. If this happens too much, the computer recognizes the tranny is slipping too much and will lock it out of overdrive. You can turn it off and then turn it back on, and it will let it go in overdrive again till the same thing happens.

I read on several forums that this stuff called "Lucas tranny fix" helped the problem go away. I read so many positives on this I tried it, and I could not believe it but it did make the problem go away for a couple of years. It's back a little bit now and I told her when she is pulling hills, to pull the shifter back in 3rd out of overdrive, and it makes the problem go away also. A major tranny rebuild with a special kit to fix that valve is the permanent fix.

 

On your code reader, open the set-up menu and drill down to language settings. Deselect "Pirate Mode" and you should be all set.

 

The preferred name of this product these days is "Lucas gender confirmation fix".

 

Does Lucas have a cousin that is a "Prince of darkness"?
Dave ----

 

It got all the way to the right side of temperature gage again and I shut it off quickly and gave the fan spin… Exactly the same as it spins when it's cold. Obviously, there is another issue because I'll get the same high temperature reading at 65 miles an hour when the fan shouldn't make that much of a difference anyway, but it looks like my fan clutch needs to be replaced regardless.

when I got home the little infrared thermometer had come in so I ran a couple errands and then tested it out. Here's what I got.

The gauge was showing just a hair above normal

Heater core hose reading 187°

Reading 213° on the metal between the heater core hose send and return

I have the thermometer in the truck now, so next time it overheats I'll take these readings again.

 

It overheated again today so I got reference numbers. By overheated I mean the gauge was showing all the way to the right, it didn't stall out or start steaming or anything like that.

After running the AC the temperature gauge went all the way to hot.
Heater core hose showing 204°
Upper radiator hose reading 205°, so just about the same as the heater core hose.
I have the red dot from the laser pointed on the metal housing between the heater core hoses, Reading 224°
i'm not sure what normal is, so I don't know what any of this means but, hopefully this will be helpful to you guys you know what you're doing. Hahah.

 

As has been suggested previously, check the temperature of the radiator inlet (top) hose connection and bottom connection while it is still running. This will give you the temperature differential across the radiator. An indication if the radiator is doing what it should.

 

204F is just where you want it. The thermostat doesn't even open till the engine gets to around 195 degrees to let water start flowing through the radiator. 224F is what temp you get when working the engine hard on a hot day. Not overheating yet. If it goes on up to 230F, and you are not working the engine hard, then I would start suspecting something. When you get that hot you can expect it to start running a little rough, the carb will start getting hot and the fuel will start boiling in the float chamber, spilling fuel into the engine.

I still suggest a real gauge installed under the dash. The infrared thermometer is not really helping much.

 

Respectfully, I'm not sure adding a mechanical gauge is really needed. He's already got two means showing the engine is running warmer with the AC on.

The first is the factory gauge. Now I get it, lots of folks think they are inaccurate. My experience has been just the opposite. Even if the gauge doesn't give a numeric value, it's very good at showing a relative reading. In this case, the gauge climbs much higher than it had been with the AC off. Unless there's a weird electrical issue driving the needle higher with the extra electrical load of the AC, I'd say to cautiously trust that relative reading.

Now, in the immortal words of Ronald Reagan, dealing with the Ruskies: "Trust but verify." That's why I suggested the infrared thermometer. This is the second means. It is also showing some increase. I was kinda puzzled, though, because I had expected to see a greater jump. Then it hit me. How long elapsed from the gauge showing hot until you could get under the hood with the infrared? Assuming (Danger! Danger!) it was several minutes, that's a lot of time for the engine to cool, especially with coolant flowing. That would skew your readings.

Try this: Pick a DESERTED road with no traffic. Duplicate the fault so the gauge shows hot. Pull over immediately and shut off the engine as quickly as possible so it has no time to cool. Time is of the essence. Think of Ralphie's Dad in A Christmas Story, when the car gets a flat. Then take your infrared reading and see what you've got. Concentrate on the temperature at the thermostat housing. That's the most important place. My hunch is you will see a big increase.

If so, you've got a legitimate hot running condition. It may not be hot enough for the steam and rough running, but it's still much hotter than it should be. To troubleshoot that, there are two main causes. Sometimes it's a combination of the two:

1) The engine may be putting out a normal amount of heat, but the cooling system isn't up to snuff so the temperature rises. An example of this is scale buildup inside the radiator, restricting heat transfer.

2) The cooling system may be operating as designed, but the engine is putting out too much heat and overwhelming it. An example of this is ignition timing out of specs or a restricted exhaust.

I bring this up to illustrate the need to confirm exactly what is happening. If the deserted road rest confirms an actual overheat, don't just start throwing parts at it. A new radiator won't fix the ignition timing, for example.

 

You say "engine off" why as you may get heat soak and being heat raises you could be getting a faulty reading.

I say take all readings, heater hose, tstat housing, top & bottom of radaitor with motor running.
Dave - - - -

 

Good point. Mostly I'm trying to eliminate any factors that will skew the results once the overheat is duplicated. That's I suggested an empty road, for example. I think he said he's only getting the fault at freeway speeds. If he gets the hot indication again in normal traffic, it's not going to be safe to pull over on the shoulder of a busy freeway. He'd have to take the next exit, maybe stop at a few lights, all in search of a parking lot or other place out of traffic. Meanwhile, since the overheat isn't present at lower speeds, the engine cools off. The infrared reading and the gauge will both show the current condition, not what it was several minutes earlier at freeway speeds. My thoughts are if you can shut down the engine as quickly as possible and take an infrared reading right away, you should get a fairly accurate indication. If done quickly enough, heat soak hopefully won't be an issue.

Heck, I may still be in left field here, but am thinking we still are not positive it's an actual overheat. Could be a funky gauge problem. That's why I want to be positive before digging any deeper.

 

You can see all those radically different readings he is getting depending on where he is pointing the thermometer. Which reading should he believe?

In my experience, the engine is a large block of iron and there is lots of coolant circulating around. If he stops and lets the engine keep running, it will take awhile before it cools off.

The only suggestion I have is to take readings with the thermometer when the engine is normal. Then compare them to when it's supposed to be overheating. You have to remember, I haven't heard anything about any spark knock, coolant over flowing or anything else. So the only reason he thinks it's overheating is because of the lousy factory gauge. And technically he is still in the "normal" region of the gauge.

 

good point. Here are the readings from today when it was supposedly overheating. As was previously suggested, this time I included a reading from the lower radiator hose. In a little while I'll drive it up to the gas station to fill it up and take the same readings when it's showing the normal vertical straight up in the middle of the guage.

200° on the heater core hose
217° on the thermostat housing
187° on the upper radiator hose
148° on the lower radiator hose
This is what the heater gauge showed while I was taking those readings

 

I don't see what value those readings provide.


Your reading the exterior surface of the radiator hose and various places on the block. How does that correlate to coolant temp?


If you took readings off another truck with same engine, at the same locations it might provide some comparison value, but it doesn't solve the problem. Is your truck running hot (and if so why) or is the gauge or sending unit faulty?


These engines can have 180 or 195 thermostats and a coolant temp of 200 - 210 is in the normal range. So what does the IR reading of 217 on the engine tell you. Is the coolant temp 217 or is the thermostat housing 217 because of heat from the exhaust manifold and cyl head migrating to the thermostat housing?

 

Here's the latest update for anyone curious as to how this plays out:

I decided to just start doing things that may or may not help but I figured were a pretty good idea regardless. I started with the radiator flush and fill which I did at home. Whatever was in the radiator was not coolant, it was water that smelled like dead fish. It smelled so bad that my wife came home hours later and asked me what smelled so bad in the driveway. I filled it back up with water from the hose and a bottle of the stuff that supposed to help clean it and drove it for a week and when I pulled from the radiator at the bottom what came out looked like it was more rust than water. I hooked the flush up to it and ran it until it ran clean and then filled it back up with water from the hose and ran it for a day. Gage still showed it was running hot, but maybe not quite as high.

When I dumped it the next day it wasn't as bad as the day before, but still mostly orange/rusty. While the coolant was out I changed out the thermostat and gasket. Filled it back up with clean water from the hose and it's been running for almost a week and it has yet to go past the "A" in "Normal". It has bumped up against it once or twice, but I dont see any pattern as to when/why.

My plan is to dump the water one more time this weekend and fill it back up with 50/50 green coolant and hope for the best.