thermostat problem?

shaun40400

my heater hose blew out on the m25 last week (Renault master 35)
ive replaced the split coupling with one from a garden center for £4-20 as Renault will only sell theirs with a hose set for £80+
took the van for a run tonight, it was ticking over for 10 mins and then ran for for 20 mins at 25/30mph,and i noticed after about 5mins of driving that the heater was not working,,
when i got home the heater still failed to generate any heat,,i did think i heard the engine fan cut in,,
1) has the thermostat gone?
2)if so would you advice a 100 mile journey with a broken stat
3) mechanical knowledge is basic ,,could i replace this myself

thanks in advance

Norman_Castle

Check the water level. You may have an airlock, Some cooling systems have bleed valves and filling proceedures to avoid airlocks. If the thermostat is stuck open the engine would be overcooling. For the fan to cut in the temperature is too high.

would you advice a 100 mile journey with a broken stat

I would not advise a 100 mile journey with a possible airlocked engine.

Strider590

I'd go with the airlock theory first, make sure you top up the coolant level and find a squidgable section of hose and squeeze repeatedly.

shaun40400

thanks for the reply's
will check after lunch what the level is at now..and do a squeeze test,

Foxy-Stoat_3

Thats if you run out of diesel use the sqeezing thing, you'll want to find the bleed screw in the coolant pipes/radiator somewhere.

Fill it up, heater on hot setting, and wait till the coolant flows out of the bleed screw, then run it up for a while and open the bleed screw again, keeping an eye on the temperature.

If the heaters go cold, temperature gauge is in the middle to hot then you have either an air lock or lost all the coolant.

Did it overheat or did you drive it while over heating?

poppasmurf_bewdley

Have you checked the replacement hose whilst the engine is hot and running? If it's not a proper reinforced hose it could well be ballooning up to a massive size, and that would affect your heater. Otherwise, I'd go for the airlock theory first.

s_b

my heater hose blew out on the m25 last week (Renault master 35)

was this due to old age or do you have a bigger problem?
maybe the thermostat stuck shut and caused this problem as i had exactly the same problem last week when the thermostat stuck shut
one new thermostat and a good bleed seems to have sorted this one

shaun40400

the van is 10yrs old
i brought it from the ni ambulance service in nov,assuming it been regularly serviced eth,,
ive done about 1000 miles in it,
their is an adapted heating system fitted to put warm air into the rear of the van,,
it was the plastic T connector that broke i pulled over with in 2 mins of covering the M25 in a large cloud of steam.
the heating was not at its best that day but is was cold and sleeting and we were only on the road for 10/15 mins
so feel it may be the thermostat
the hose's are in good condition,i replaced the T piece and topped up with anti freeze ,,
will look to see if i can find a bleed screw to do foxy-stoats test

mikey72

You will probably find the rear heater has the airlock, they're a pig to bleed, usually the valve is back there, or you'll need to crack the hose off in the back, and let the coolant run through.

shaun40400

gee thanks mikey i think?

is their only the one bleed valve on the system?any hints as where to look?
rear heater bleed i assume under the van not inside?
if it comes to bleeding the rear heater then nearer the heater not the engine end?
which will be fun with the engine running!

Norman_Castle

if it comes to bleeding the rear heater then nearer the heater not the engine end?
which will be fun with the engine running!

DONT try to bleed the system with the engine running!. Cooling systems are under pressure when hot. If you open a bleed screw or remove a fitting or the radiator cap coolant will escape as steam. Let the system cool before working on it.

rear heater bleed i assume under the van not inside?

Air is lighter than water so bleed screws are normally above what is beig bled.