Hello, this is my first post here, so a quick intro, then onto the big question

I have a 91 Volvo 240 wagon that I bought for my other half. I got tired of fixing the troublesome American car, and I'll leave it at that.

I'm a Mercedes enthusiast, and an auto mechanic by trade. So vehicles, especially quirky European ones don't scare me. And this Volvo is one simple car, well, mostly. I have a million of my own projects, and was hoping this could be a nice, simple, "set it and forget it" car. I realize there's no such thing, but my intentions were to just replace everything then let it roll. I have yet to do most of it... but in my experience with European cars, as long as they're free of rust, replacing all the wear items will generally create a very dependable, and long lasting car.

The 240 is in nice shape, I picked it up with 138K miles on it, and a monsterous stack of service records. It was fairly well cared for, and was purchased from the original owner. It was dealer serviced for much of its life, and is rust free.

Even after replacing the rear subframe bushings, it still makes horrible noises, and rides like a lumber wagon... I'll get to my questions about that in another post.

The problem at hand here is the heater. As the weather got colder, the heater was not working well. I pulled the thermostat out, and it was broken apart, so I replaced it.

I refilled the coolant, and the temp gauge warmed up to just shy of halfway on the gauge, the heat was powerful, and worked well. It's been fine for about 3 weeks.

Today, it's 18F degrees, and the heat is very much lacking. The temp gauge is barely breaking loose. Is it common for these cars to run cold in cold weather... or could a thermostat have failed already in just a few weeks?

I know about all of the screwy temp board issues, but the temp gauge wouldn't have any effect on how much heat the heater produces, actually the temp gauge seems to be fairly "accurate" in that sense.. when the engine is cold, it reads cold, and when the engine is up to temperature, it reads just shy of halfway, or exactly halfway.

The engine is just not getting warm in this cold weather.

Before I drain the coolant and crack open the thermostat housing, is there something I could be overlooking??

Thanks in advance for any suggestions.

-Aaron

 

I'd check that A) the engine and radiator are getting hot enough and B) that the heater valve is opening properly.

if the radiator isn't getting hot (I usually just check the top hose going from the thermostat to the radiator), then its a thermostat problem. if thats hot, and the heat is not getting to the heater core, then its a heater valve problem.

we had to replace the heater valve on our 87, its a simple cable operated valve, but the earlier ones had a copper thermo tube to regulate the temperature, and those fail, then the valve stops working right. I ended up replacing it with a heater valve from a 70s dodge truck or something, plus some bits of hose, actually I got this guys kit...

Volvo 240 heater valve kit replaces 1348252 9131998 $59! Volvo 240 heater valve kit replaces 1348252 9131998 $59 [] - $59.00 : EuroPartsHouse

very easy to install, you remove the drivers side kick panel, and its right there tucked into the console near the gas pedal. There's a link to instructions with pictures on that site, so you can see how easy it is.

p.s. your heater hoses, between the back of the head and the firewall, are likely 20+ years old. I replace those on most any older car I get at the first opportunity on principle, unless they look brand new.

 

If the temp gauge needle is not moving it sounds like your thermostat is stuck open again. What brand of thermostat did you install? I only use Wahler as that is what OEM is. Since you are in the northern climate, I believe it came with a 92 degrees C thermostat. That is what I use (in Chicago area).

 

Thanks for the replies.

I'll check it later this evening to see how warm the upper hose feels.

I have no idea what brand thermostat it was. It's whatever the Advance Auto Parts store had in stock. The guy there was so smart that when I sent someone after the thermostat, they were told it didn't need an O-ring, and instead sent a tube of silicone. They're pretty brilliant there.

I went back myself and explained to them that it wasn't a small block Chevy, along with supplying them with their part number for the o-ring which they did have in stock. I was pretty happy that day.

The new thermostat did appear to be of marginal quality, but then again, I haven't seen an auto part in a few years that appeared to be of good quality. Heck, even Bosch diesel injectors are made in India or Brazil now, I've seen many defective new parts lately.

End rant- I'm just surprised anyone could screw up a thermostat... but I will heed your advice and purchase an OEM thermostat. I've found with Mercedes that some OEM parts are mandatory as well, the problem being what you can get locally on a Sunday afternoon...

On the flip-side of things, the coolant is NASTY. I intend to flush it, but in sub-freezing temperatures, it's just not the best time. Certainly nasty coolant can cause its share of problems, but nothing seemed to be plugged, and no matter how bad it is, it can't be both functional and corrode a thermostat in a few weeks, so I doubt that's the case. The coolant tests ok down to below -45F degrees, so at least it's not going to crack anything expensive.

This is just such a stupid problem for such a simple car!

I'll report back with my findings.

Thanks again,

-Aaron

 

Ok, today it was about 20F degrees, and the heat worked ok, the temp gauge climbed normally, although it never got to its horizontal position.

It also idled in the driveway for 1/2 hour before leaving, so that could have helped get it warmed up.

I guess I should pull an inspect the thermostat this weekend. Bummer.

 

your water pump could be on its last legs if its original. it should have been replaced with the 2nd timing belt at 120k. if that wasn't done, you're on borrowed time. usually they fail at the seal, dripping coolant out the weep hole (which is a warning, you can still go a bunch of miles til you have to replace it), but also the rotor can get eroded away and they stop pumping efficiently.

 

If the water pump were going bad, then I would expect high readings on the temp gauge instead of low ones. Still, it doesn't hurt to check it.

 

The water pump was replaced by the dealer when the timing belt was replaced.

A water pump would most certainly cause the engine to overheat if it was failing, this issue is a lack of heat.

I suppose a lack of output at the heater itself could result, but I'd expect the engine to be burning up simultaneously- it's not.

 

true.

yeah, if the engine itself gets warm, but the top hose and radiator isn't, then I'd be cracking open that thermostat housing again to see WTF?

i pulled a like-new offbrand thermostat out of my wife's Benz (1994 E320 3.2L dohc inline 6 wagon, a very sweet ride), it was cracked and jammed open so the engine never got up to proper operating temperature. I replaced it with a Wahler or whatever the OE MBZ 'stats were, had no trouble since. The PO was a retired aircraft engineer and did everything on the cheap. had to fix lots of deferred maintenance, but the car itself is cherry.

 

My '93 240 Wagon has the opposite problem: When I switch the lever from hot air to cold air, it gets a little cooler, but it's still pretty warm. I tried adjusting the cable to make sure the valve traveled the whole distance, and it does. Then I tried taking the valve out to make sure it was operating, and it is.

Here's my question: when this valve is closed, should it be a tight close that lets nothing through? I can blow through it when it's closed. Is that normal?

Thanks,

Eric Z.

 

I would say it's leaking.

I noticed last summer, that if the valve wasn't 100% closed, the A/C felt like it was barely working.

I'm sure it should completely cut off flow in the closed (cold) position.

 

Good to know. It sounds like I should replace that valve.

Thank you!