Has anyone ever had a thermostat, water pump, or radiator go bad on them after a coolant change? I changed my '93 240 coolant and hoses, and can not get any of the coolant into the block, it is all built up in the radiator and expansion tank. Would the thermostat not open up if there is no hot fluid present? I allowed the engine to warm up and shut it off right before it got into the red. Should I just take the thermostat off and run the engine to just get fluid into the block? The fluid was clean when I emptied the system (no rust or chunks) and I did not flush the system.

 

So...you swapped hoses. Did you touch the thermostat? There's obviously some quantity of coolant in the block or it would not read hot. Temp gauges won't work if they are sitting in air. To fill the system, you have to run the engine to have the thermostat open while adding coolant. Occasionally, you can get a bubble to form that causes an airlock. Frankly, I've never had a similar issue unless I swapped out the thermostat. Occasionally, squeezing the rad hoses will release a bit of air.

 

Well, I tried warming it up again, this time while driving it around. Temp gauge was right below the red like once before, and it just went down to normal operating temperature and the heat works. I'm thinking the thermostat was just stuck close... Thanks though...

 

Hi,
I am the tech manager at Prestne coolants. Proper oreintation of the tstat is critical-
Volvo TSB-
NUMBER
204/910
MODEL
200/700-900
GROUP
26
TITLE
INSTALLATION OF COOLANT
THERMOSTAT
240/700/900 1976-->
W/ 4 CYLINDER ENGINES
MARKET
US and Canada
DATE
February 1993
REFERENCE:
TP31614/1(ENGLISH); 06/90; ENGINE B19, B23, 740/760 1983-84
TP 31311/1 (ENGLISH); 12/88; B204, B234 ENGINES, 740 1988-19..
TP 31003/1 (ENGLISH); 05/87; B200, B230 ENGINES, 740/760 1985--19..
TP 30163/2 (ENGLISH); 02/85; ENGINES B17, B19, B21, B23
Installation of coolant thermostat

When replacing a coolant thermostat, dated 12/2 (December '92) or later, ensure that the venting nipple is facing upward (as illustrated). The nipple is so small that it may not be noticed. Thermostats dated before 12/2, should be installed with the nipple at 10 o'clock or 2 o'clock.
An air pocket may form in the top of the thermostat housing if the nipple is positioned incorrectly (facing downward), resulting in improper operation.
Please enter the note, "Also see SB 26-910"
at the top of page 176 and on page 181 (operation A8) of Service Manual, TP 31614/1 on page 243 (operation AQ3) of Service Manual, TP 31311/1 on page 58 (operaion AB2) of Service Manual, TP 31003/1
Please enter the note, "Also see SB 26-204" on page 82 (operation A12) of Service Manual, TP 30163/2

Service and Repair

1. Fill system with coolant.
2. Start engine and allow to reach normal operating temperatures.
3. Set heater control to warm position.
4. Shut engine off and check coolant level, add coolant as necessary.

 

Unfortunately, I'd say more than half the replacement thermostats on the market...do NOT have the bubbler valve. It isn't critical, just convenient. I doubt the thermostat was stuck...more likely there was an air lock bubble. It worked out and now you're good to go.