Here we go,
Bought a Volvo 244DL and it has a suspected overheating issue. Upon start up the needle climbs and stops dead right before the red. Today I decided to flush the cooling system and check out the thermostat. Loosened and eventually took out the drain caulk but no flow, decided just to skip that step for now and moved on the radiator outlet hose. Disconnected that and low and behold about a gallon and a half poured out. Coolant looks real clean. Messed around with where the caulk screwed in but it didn't provoke flow. Pulled out the thermostat and it was stuck open, which doesn't make much sense to me, and it remained open in cold tap water. I am about to pull the temp sensor and test the resistance but was just looking for some outside opinions.

 

hello, I think you are referring to the radiator drain petcock. It could be blocked with debris.
With the radiator hose off, you could flush water through it to see if that loosens up some gunk.
However, I'd start with a new thermostat first. It should be closed when cold and open when hot.
Don't touch the temp sensor.

 

Hey admasters,
The video I watched online (longbow media) drained coolant from the radiator via the outlet hose and a drain petcock in the block. It's on the passengers side of the engine underneath and just behind the exhaust manifold. I can look for one on the underside of the radiator but I don't think it matters much if I can just disconnect the hose. I like your idea of just starting with a tstat as mine is definitely faulty and I'll pick one up tomorrow. I did some more research and it looks like there might be a sensor for the gauge alone and another for the ECU? I'll leave them alone for now but feel free to correct me I am fairly new to Volvos. Another interesting thing to note is the thermostat reads 87 degrees on the bypass valve along with some other random numbers and "WAHLER VOLVO". 87 degrees is way too cold for a thermostat as far as I know I'm used to seeing them around 195-ish.
Thanks for the reply

 

87* is Celsius which is 188* F.

 

Ah, that makes a whole lotta sense. Just got too used to looking at domestic cars I guess.

 

My biggest concern is that the needle isn't reading accurately, or it is and the engine is just always that hot. Upon start-up, it slowly rises with the fuel gauge alongside it and hits the same point just before red every time. I shot an IR temp gun at the thermostat housing and got about 150-160ish* F. It'd kind of make sense that it's that cold as I measured this with the tstat out as it was stuck open and I'm flushing the cooling system with distilled water. But the gauge still sat high. Unless that's the normal spot for the gauge to sit I think it could be the temp sender with that rinky dinky little yellow wire. I checked out the female connector that attaches to the block and it looked clean enough, no visible corrosion or debris. Hoping some smart dude can help me out.
Thanks and sorry for being the newbie, just want to iron out these wrinkles and for this car to last a long time

 

Have you read this:

https://cleanflametrap.com/tempFaker.html

 

Thanks act that website is super helpful. Will definitely look into that.

 

If you go to the root (cleanflametrap.com) there are a lot of useful links for debugging problems from fuel pumps to blower motors to speedometers. I learned a lot from the gentleman who created the site.