Cooling system - specific fault or general wear?
Discussion
Today on my drive to work I got stuck in traffic, taking about 10 minutes to cover 1/4 mile (festival goers in shepton mallet!). The sprint got a little warm, reading just under 100. Warning light came on when I was just arriving at work, and it spat a little coolant out of what from what I guess is an overflow. This was with precautionary measures like having the heater + heater fan on full from the point of hitting the traffic.
My question is, is this likely to be a specific fault or just general wear and tear through the whole system? as far as I can tell its all working - heater works, no evidence of airlocks, car runs a bit below the middle on the temp gauge normally, always warms up to the middle (80) or a shade above if provoked by 'normal' traffic.
Its the alfa boxer engine, 1.7, slightly tuned but nothing much.
My question is, is this likely to be a specific fault or just general wear and tear through the whole system? as far as I can tell its all working - heater works, no evidence of airlocks, car runs a bit below the middle on the temp gauge normally, always warms up to the middle (80) or a shade above if provoked by 'normal' traffic.
Its the alfa boxer engine, 1.7, slightly tuned but nothing much.
not a real help but...
did happen to me once under almost the same circumstances. i was driving 1mph and 0mph for almost an hour and the engine overheated... and the reason it did is that the weather was damn hot (around 40 celsius) and i was driving in the middle lane, in a 4-lane road - so i was surrounded by very hot cars as well - breathing exhaust gas instead of normal air.
did happen to me once under almost the same circumstances. i was driving 1mph and 0mph for almost an hour and the engine overheated... and the reason it did is that the weather was damn hot (around 40 celsius) and i was driving in the middle lane, in a 4-lane road - so i was surrounded by very hot cars as well - breathing exhaust gas instead of normal air.
Cooling systems are tricky beasts. The worst case condition can come from different scenarios:
- Sitting at tickover
- Slow speed, high load (climbing a steep hill in second gear, for example)
- Heat soak after switching off.
It doesn't sound like you have a specific problem, but keep an eye on it now you've seen a problem, and you should consider how to maximise efficiency through each stage of the system. I look at it this way:
1) Heat Sources
That's combustion and friction, so:
- Is the engine properly tuned (a weak mixture can produce higher combustion temperatures)?
- Is your oil OK, and properly topped up? Low oil means more friction (more heat energy), and less removal of heat (through the sump and cooler) which has to go somewhere else.
2) Heat Transfer Into The Water
- Have you got the right coolant mixture? A £5 tester from Halfords will tell you.
- Is the system sealed/pressurised properly (leaks, cap)? Pressurising the coolant allows it to run a bit hotter without boiling. Check the manual/Haynes for figures.
(N.B. As I assume that your breather is off the cap, I would assume that this is OK)
3) Is The Water Circulating?
- Is the pump working? Potentially a belt slipping (screeching noise). Possibly damaged vanes (pretty serious, and last resort. Shows itself particularly at low rpm)
- Is the thermostat stuck partially open (blocking the flow)? You will find temperatures are a bit higher particularly in urban, and also that changes are slower (slow to warm up from cold, because it hasn't shut; slow to drop back when you are able to cruise on the open road)
- Is the system blocked with sludge? Same symptoms as the thermostat. You can try flushing it. You can take off the bottom hose and feel around in the hose and radiator for goo.
4) Is heat being properly taken from water to air?
- Any blockages on the air side of the radiator 9crisp packets, excessive dead flies)?
- Is your fan working, cutting in at the right temperature, spinning freely?
Each of these will add a few degrees to the 'safe ambient temperature' the system can endure. Some are easy to check and cheap to fix, others aren't. Just try to maintain each at optimum efficiency.
In your case, I'm guessing the ambient was pretty extreme (high air temp, no flow), although it was rather early in the morning. All mass production cars should easily clear 30 degrees ambient, and be pretty good up to 40 degrees. It doesn't sound like a fatal flaw, but I would recommend monitoring the situation and giving it a bit of TLC - a pot of Radflush is slightly cheaper than head gasket replacement, after all.
- Sitting at tickover
- Slow speed, high load (climbing a steep hill in second gear, for example)
- Heat soak after switching off.
It doesn't sound like you have a specific problem, but keep an eye on it now you've seen a problem, and you should consider how to maximise efficiency through each stage of the system. I look at it this way:
1) Heat Sources
That's combustion and friction, so:
- Is the engine properly tuned (a weak mixture can produce higher combustion temperatures)?
- Is your oil OK, and properly topped up? Low oil means more friction (more heat energy), and less removal of heat (through the sump and cooler) which has to go somewhere else.
2) Heat Transfer Into The Water
- Have you got the right coolant mixture? A £5 tester from Halfords will tell you.
- Is the system sealed/pressurised properly (leaks, cap)? Pressurising the coolant allows it to run a bit hotter without boiling. Check the manual/Haynes for figures.
(N.B. As I assume that your breather is off the cap, I would assume that this is OK)
3) Is The Water Circulating?
- Is the pump working? Potentially a belt slipping (screeching noise). Possibly damaged vanes (pretty serious, and last resort. Shows itself particularly at low rpm)
- Is the thermostat stuck partially open (blocking the flow)? You will find temperatures are a bit higher particularly in urban, and also that changes are slower (slow to warm up from cold, because it hasn't shut; slow to drop back when you are able to cruise on the open road)
- Is the system blocked with sludge? Same symptoms as the thermostat. You can try flushing it. You can take off the bottom hose and feel around in the hose and radiator for goo.
4) Is heat being properly taken from water to air?
- Any blockages on the air side of the radiator 9crisp packets, excessive dead flies)?
- Is your fan working, cutting in at the right temperature, spinning freely?
Each of these will add a few degrees to the 'safe ambient temperature' the system can endure. Some are easy to check and cheap to fix, others aren't. Just try to maintain each at optimum efficiency.
In your case, I'm guessing the ambient was pretty extreme (high air temp, no flow), although it was rather early in the morning. All mass production cars should easily clear 30 degrees ambient, and be pretty good up to 40 degrees. It doesn't sound like a fatal flaw, but I would recommend monitoring the situation and giving it a bit of TLC - a pot of Radflush is slightly cheaper than head gasket replacement, after all.
In theory yes, but in practice it's relative to what it should be on your car (which of course you don't know). Though if you get something after 30-60 secs, then there's probably an issue.
Remember, of course, to check just after the thermostat, and from true cold (early morning?) so you can feel the difference. If it's easy to reach, it may be worth popping it out, putting it in a saucepan, and boiling it up to see when it opens and if it moves freely. Or just replace it.
Remember, of course, to check just after the thermostat, and from true cold (early morning?) so you can feel the difference. If it's easy to reach, it may be worth popping it out, putting it in a saucepan, and boiling it up to see when it opens and if it moves freely. Or just replace it.
not sure what to do about preventing airlocks.HiRich said:
- Is the system blocked with sludge? Same symptoms as the thermostat. You can try flushing it. You can take off the bottom hose and feel around in the hose and radiator for goo.
I would recommend monitoring the situation and giving it a bit of TLC - a pot of Radflush is slightly cheaper than head gasket replacement, after all.
Can you get the Rad out easily?
I'd get it out and give it a blast thro with a hose.
It does sound like an 'older car' problem. I've had this too many times to count. Flush it then keep an eye on it unless you like head gasket replacements and all that entails.
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff