Forum:
Hi, bought my first Daihatsu yesterday, a 97 sportrak. a winter vehicle. was told may overheat ... and it did .. previous owner did a flush and new thermostat last year. Drove 110 miles, first hour Ok, then gauge went to 3/4 then down and moved up and down from half to almost over heat until it went to over heat. I was on the motorway at the time.
stopped and expansion bottle was overflowing but water clear and blue ... fits in with recent flush done by owner who cared for it well.
left it five mins and it cooled, but soon overheated again, stopped, expansion overflowing.
had to stop three times in all.
Today i watched closely, no probs on a short run but went to middle of the temperature gauge after about four mins.
Have read posts on previous, same issues, is mine common, is there a coomon prob ... ie the fan? should it be working to cool ...
Interesting point was the gauge rising and dropping back to the middle ....I rolled down a steep hill and put in neutral to get air flow and low revs .... temp still went up ....
loving my Sportrak ..... learning about cars as I go ... I want to learn about vehicle maintenance .... I do senior management stress Mon-Fri, want to enjoy my Sporty at weeekends ..
Thanks
Nick
Head Gasket.
If the coolant is flowing out from the coolant reservior then the fault is easily diagnosed. The cylinder head is the fault. At minimum it is a blown head gasket - relatively inexpensive to fix - get a quote possibly
Oh nooooo
Many thanks for your comprehensive reply ..... was hoping you weren't going to say that ..... a bit more background for you ....
Water in expansion tank was bubbling, I took out tube and sniffed, no smell of oil/fuel etc.
Rocker cover/oil cap shows no whitening.
Previous owner states that when car overheated on them, RAC sniffed rocker area and expansion tank and no gasses evident ....
Car bought as seen, cash .... family were genuine .... was taken to nice house, car on drive, cold started, previous owner has spent a fair bit on it body and mechanical wise .... last MOT was
Answer these .........
Nick.
If the compression is escaping into the coolant, the oil will not be contaminated. The leak is possibly into the coolants head 'jacket' rather than into an oilway. Hence no white/brown 'deposits' inside the rocker box, on the dip stick, or oil filler cap.
Next question ........
1. When it overheats is coolant in the reservoir adding volume [the bottle level will significantly rises] or is coolant being expelled out from the reservoir overflow?
2. Does the coolant need topping up following an overheat?
3. Remove the radiator filler cap ....even though coolant exists in the reservoir, check the radiator is full to radiator's cap. Following oveheating and unaware to you, the radiator could be low on coolant even though the coolant reservoir is full..
4. Is the coolant boiling, bubbling, or bubbling and boiling?
5. When starting from cold [especially after an overheat] is there a noise of gurgling from the heater matrix or engine block?
PS ... I recommend no driving until sorted.
Here goes
1. When it overheats is coolant in the reservoir adding volume [the bottle level will significantly rises] or is coolant being expelled out from the reservoir overflow?
Both, it fills reservoir then expels it.
2. Does the coolant need topping up following an overheat?
Yes
3. Remove the radiator filler cap ....even though coolant exists in the reservoir, check the radiator is full to radiator's cap. Following oveheating and unaware to you, the radiator could be low on coolant even though the coolant reservoir is full..
Radiator was full before I drove it home and expansion bottle at full marker.
4. Is the coolant boiling, bubbling, or bubbling and boiling?
bubbling and boiling, took out tube, no smell of fumes.
5. When starting from cold [especially after an overheat] is there a noise of gurgling from the heater matrix or engine block?
No matrix noise.
I spoke to previous owner and he re-confirmed that coolant was sniffed at garage and no fumes detected.
Going to give it a good flush, could it be the wrong thermostat? Where do I check if it is right one?
Could radiator be blocked?
Thanks again
Nick
OK next ........
Nick.
Boiling could be a thermostat fault. Bubbling is gas escaping from the coolant. Bubbling and boiling together is 99% a blown head gasket or cracked cylinder head.
You could ask a garage or Halford to do a 'compression test'. This would show if any cylinders are low on pressure and leaking into the water jacket. Tell them the coolant reservoir expells water when the engine is hot. Any head gasket leakage may only show when the engine is hot. The test is very quick - they remove in turn, spark plugs and test the cylinder pressures.
Radiator ....
1. drain tap is at the radiator's inside bottom edge. Drain the radiator.
2. use a garden hose and flush through the radiator for 5 minutes.
Then
1. remove the top hose from the radiator. Take care not to crack the weld where the plug is soldered into the top tank. [if you try removing the bottom hose is is likely to prove difficult or likely to break the solder at the joint.]
2. reverse flush the engine block. Flush through the top hose so the water runs through the engine block and out the radiator filler.
Then
1. if you can undo any visible coolant hose, you can flush through the engine with the hose pipe.
2. reverse flush also.
Thermostat.
Might be worth renewing but I doubt if this is the fault. When you fit a new thermostat use some none-hardening gasket sealant. Fit with the 'jiggle' uppermost so any trapped air escapes via the engine block. ['jiggle' is the small hole in the thermostst topplate]. The thermostat housing will leak if you failto use sealant + new gasket. ONLY TORQUE THE 3x bolts TO 5 LBS. Any greater ant the bolts snap off!
Sporty thermostats are much longer than normal thermostats. Make certain the motor shop sell to you a longer reach thermostst for Sportrac - they will check the type in catalogues. Costs about