It still runs fine and doesn’t get TOO hot (or cold). It will get 2/3s of the way up the temp scale (and continue to climb until i intervene) in the summer if it’s hot (90+) out and I’m driving >70. If I’m less than 70mph, it only gets about half-way hot (of little concern).
In the winter, it barely gets to 1/3 warm. If it’s cold out (<40), the water temp may never get that warm.
More info; I can see the temp needle moving up or down in response to my foot. If I’m pushing and going fast or powering up hills, I’ll see it climb. If I back-off the speed and/or coast down the hills, I can see the needle fall a bit. I do not run the AC but if I did, the water temp would get alarmingly hot (which is why I don’t run the AC). It cools to a reasonable temp (half-way hot) when sitting in traffic.
Plenty of water/AF cocktail in the radiator. As of this typing, I’m not sure what the overflow tank has in it, though.
Your thoughts/speculations/humor/advice would be appreciated.
Bad thermostat would be my first guess. Cheap part; usually pretty easy/cheap to replace.
Bad radiator cap is not common, but $10, a good idea to replace from time to time and a two-minute job as long as you’re smart enough to let the engine cool first.
Possibly not enough cooling capacity for the conversion - big vehicle built to “save every ounce and nickel” spec and then loaded with heavy gear. I would assume the conversion folks covered this and at least included the “tow package,” but… that doesn’t really square with the “too cold” in winter unless you mean really cold weather.
T’stat was my suspicion, too. I wanted to hear it from someone else, ha! And I’m assuming that bad = stuck partially open/closed, restricting flow when needed but allowing flow when it shouldn’t… right?
I don’t think it’s the cap because the water level stays constant. I do not have to add water to the system. But as you mentioned… cheap and easy to replace.
Also concerning the “oversized demand mated with limited cooling capacity” concept, I agree that the winter problem sorta negates that possibility. At least in this specific situation.
Right. The thermostat holds back water flow to keep the water around the heads and cylinders up to a certain optimum temp, opening only when it exceeds that level, and sometimes opening and closing in really cold weather to keep the heads hot and burning efficiently. If it sticks open, the engine will run cold. If it sticks shut, engine will overheat.
Usually a half-hour job on a newer V8 if you’re a middling mechanic, should be no more than $50-60 at a fair shop.
I agree with Gary here. It sounds like someone had removed the thermostat because of an overheating problem. Possibly bugs in the radiator restricting air flow or radiator plugged internally with gunk. Has the car always been like this?
I would guess you need a radiator flush in addition to a new thermostat. There may be a lot of gunk plugging it up in various places from time to time. If it restricts the flow somewhere, you get overheating; if it gets stuck in the thermostat itself, it runs cold. A new car needs a flush every three or four years, and a 94 should probably have one once a year. I have a 94 Acura that I got flushed once a year, and it ran perfectly at temp in all kinds of weather.
If you have the space to do it, a flush can be a DIY, but it can be messy, and you need to dispose of the toxic stuff you drain from the radiator properly. If you decide to go to a mechanic to have the thermostat replaced, get a flush and fill, and have the hoses replaced. It will be worth it. It will add life to the engine.
I did a flush a couple of seasons ago, mirroring your concerns, Rivkah. It didn’t have any noticeable effect, though.
The van’s been doing this as long as I’ve had it (~3 yrs), but I don’t drive it often. It’s been on my mind lately because I have had to drive the van every day for the last couple of weeks (we’re moving, cleaning, etc).
The overheating is concerning, but I can work with it (i.e. slow down) and predict its behavior. I can let the van idle a little while on the super-cold mornings before I start *blowing *cold air through the coils, but I’d rather not.
I’m going to check/change the T’stat and flush the radiator while I’m at it. Actually, I’ll probably take it to the shop this time. I’ve got to get it inspected for its registration renewal anyway.
A system flush is a good preventive maintenance procedure, but hardly ever opens up a clogged radiator. Sometimes, depending on the radiator’s construction, a “rod out” procedure can be done to clean the restrictive deposits out of the radiator’s tubes. Most of the time, though, it’s necessary to replace the radiator to solve the problem.
In this case, given that it’s been flushed before to no avail, don’t even bother. It won’t do you any good.
it sounds like the thermostat is stuck partially open. that’s the only explanation I can think of for running too cool in winter but too hot in summer.
I have seen cars where the owner was convinced the car was running hot. They added fans, extra cooling radiators, etc trying to cool it down. Some cars will run with the guage reading about 220 and that is fine. As far as the progresssive type guages without temp readings I would think 2/3 of the way up might be too hot or marginal if the guage is reading right.
Very easy with modern cars to hook thm up to a computer and view the cooling system going through its paces. You can see when the fans come on, when the thermstat opens and where it levels out if it does level out.