01 Civic Ex occasional overheating and coolant smell
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01 Civic Ex occasional overheating and coolant smell
Hi, I have an 01 Civic Ex. I have had a new water pump, timing belt, thermostat , radiator and new hoses put on it. The thermostat ,fans and radiator flow have all been checked and are working great. Checked for combustion in the radiator and there was none so head gasket is good. There is a definate antifreeze smell, and it smells like it is coming from around the timing chain cover area but there are no visible leaks. The water pump and timing belt were done by someone other then my usual mechanic. My mechanic did notice the bolt from the timing belt tensioner is backing out . I'm going to take it back to the other mechanic to fix that and hopefully they will see the antifreeze inside the cover and discover the cause. The weird thing is that usually the car sits right in the middle on the temp gauge, but if it has been in some traffic going up a slight uphill grade, the car overheats.
Hysterically Calm
Joined: Jan 2013
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Re: 01 Civic Ex occasional overheating and coolant smell
Air in the coolant system. The car needs to have the coolant system purged of air to stop the overheat issue. If you don't the air pocket will grow and the overheating will become worse and worse.
Until you find the leak in the system, this will be an ongoing issue with adding coolant and purging the system of air.
Until you find the leak in the system, this will be an ongoing issue with adding coolant and purging the system of air.
Honda-Tech Member
Joined: May 2015
Posts: 91
Likes: 1
From: Las Vegas, NV
Re: 01 Civic Ex occasional overheating and coolant smell
Hi, I have an 01 Civic Ex. I have had a new water pump, timing belt, thermostat , radiator and new hoses put on it. The thermostat ,fans and radiator flow have all been checked and are working great. Checked for combustion in the radiator and there was none so head gasket is good. There is a definate antifreeze smell, and it smells like it is coming from around the timing chain cover area but there are no visible leaks. The water pump and timing belt were done by someone other then my usual mechanic. My mechanic did notice the bolt from the timing belt tensioner is backing out . I'm going to take it back to the other mechanic to fix that and hopefully they will see the antifreeze inside the cover and discover the cause. The weird thing is that usually the car sits right in the middle on the temp gauge, but if it has been in some traffic going up a slight uphill grade, the car overheats.
If you are losing coolant, there is a leak somewhere. It could be leaking internally (from a cooling jacket into a combustion chamber).
If the engine was overheated (even for a short time) there is likely a warped head and/or blown head gasket.
Cylinder head warpage inspection is VERY IMPORTANT on these engines. I learned this the hard way. Qualified Honda mechanics are rare & valuable today! :-)
Honda-Tech Member
Joined: May 2015
Posts: 91
Likes: 1
From: Las Vegas, NV
Re: 01 Civic Ex occasional overheating and coolant smell
I just noticed this as a very good question. The OP wrote, "My mechanic did notice the bolt from the timing belt tensioner is backing out." Why did your mechanic have the cover off to see this? :-)
Honda-Tech Member
Joined: Aug 2019
Posts: 3
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Re: 01 Civic Ex occasional overheating and coolant smell
Hi Black Belle,
I can't say that this is what's going on in your case, but I'm dealing with something that sounds similar.
I was getting antifreeze smells, and leaking from unknown locations. I was having to purge air from the system constantly, and eventually I had overheating events. I sent it to the mechanic to have the cooling system pressure tested and it held pressure just fine. I could idle it for 3 hrs and not get the same leaking and loss of coolant I'd get from driving it to work. Somewhere, there was air getting into the system and pushing out the coolant.
As it turns out, it was a blown head gasket after all. Combustion air(not exhaust) was leaking into the cooling lines during the compression phase, but only when the engine was put under load. While driving, air was getting into the system through the engine and pushing the coolant out of the overflow reservoir where it would then be pushed onto the exhaust manifold and all over then engine.
The car is a 2001 Acura 1.7EL(a Canadian Honda Civic EX). Do you have around 190,000 miles on it.....
Next time you purge the cooling system, leave the radiator full, but the reservoir empty. Go for a nice highway speed drive (1/2 hr). Then check the reservoir. Is it full to the rim, or even just over the "FULL HOT" line? If so, you can be pretty sure the head gasket is shot. At least that's what I've got going now, and a Honda mechanic mentioned to me that it's more common than you'd think with Hondas of this generation.
Hope this helps.
Terry
I can't say that this is what's going on in your case, but I'm dealing with something that sounds similar.
I was getting antifreeze smells, and leaking from unknown locations. I was having to purge air from the system constantly, and eventually I had overheating events. I sent it to the mechanic to have the cooling system pressure tested and it held pressure just fine. I could idle it for 3 hrs and not get the same leaking and loss of coolant I'd get from driving it to work. Somewhere, there was air getting into the system and pushing out the coolant.
As it turns out, it was a blown head gasket after all. Combustion air(not exhaust) was leaking into the cooling lines during the compression phase, but only when the engine was put under load. While driving, air was getting into the system through the engine and pushing the coolant out of the overflow reservoir where it would then be pushed onto the exhaust manifold and all over then engine.
The car is a 2001 Acura 1.7EL(a Canadian Honda Civic EX). Do you have around 190,000 miles on it.....
Next time you purge the cooling system, leave the radiator full, but the reservoir empty. Go for a nice highway speed drive (1/2 hr). Then check the reservoir. Is it full to the rim, or even just over the "FULL HOT" line? If so, you can be pretty sure the head gasket is shot. At least that's what I've got going now, and a Honda mechanic mentioned to me that it's more common than you'd think with Hondas of this generation.
Hope this helps.
Terry
Honda-Tech Member
Joined: May 2015
Posts: 91
Likes: 1
From: Las Vegas, NV
Re: 01 Civic Ex occasional overheating and coolant smell
Hi Black Belle,
I can't say that this is what's going on in your case, but I'm dealing with something that sounds similar.
I was getting antifreeze smells, and leaking from unknown locations. I was having to purge air from the system constantly, and eventually I had overheating events. I sent it to the mechanic to have the cooling system pressure tested and it held pressure just fine. I could idle it for 3 hrs and not get the same leaking and loss of coolant I'd get from driving it to work. Somewhere, there was air getting into the system and pushing out the coolant.
As it turns out, it was a blown head gasket after all. Combustion air(not exhaust) was leaking into the cooling lines during the compression phase, but only when the engine was put under load. While driving, air was getting into the system through the engine and pushing the coolant out of the overflow reservoir where it would then be pushed onto the exhaust manifold and all over then engine.
The car is a 2001 Acura 1.7EL(a Canadian Honda Civic EX). Do you have around 190,000 miles on it.....
Next time you purge the cooling system, leave the radiator full, but the reservoir empty. Go for a nice highway speed drive (1/2 hr). Then check the reservoir. Is it full to the rim, or even just over the "FULL HOT" line? If so, you can be pretty sure the head gasket is shot. At least that's what I've got going now, and a Honda mechanic mentioned to me that it's more common than you'd think with Hondas of this generation.
Hope this helps.
Terry
I can't say that this is what's going on in your case, but I'm dealing with something that sounds similar.
I was getting antifreeze smells, and leaking from unknown locations. I was having to purge air from the system constantly, and eventually I had overheating events. I sent it to the mechanic to have the cooling system pressure tested and it held pressure just fine. I could idle it for 3 hrs and not get the same leaking and loss of coolant I'd get from driving it to work. Somewhere, there was air getting into the system and pushing out the coolant.
As it turns out, it was a blown head gasket after all. Combustion air(not exhaust) was leaking into the cooling lines during the compression phase, but only when the engine was put under load. While driving, air was getting into the system through the engine and pushing the coolant out of the overflow reservoir where it would then be pushed onto the exhaust manifold and all over then engine.
The car is a 2001 Acura 1.7EL(a Canadian Honda Civic EX). Do you have around 190,000 miles on it.....
Next time you purge the cooling system, leave the radiator full, but the reservoir empty. Go for a nice highway speed drive (1/2 hr). Then check the reservoir. Is it full to the rim, or even just over the "FULL HOT" line? If so, you can be pretty sure the head gasket is shot. At least that's what I've got going now, and a Honda mechanic mentioned to me that it's more common than you'd think with Hondas of this generation.
Hope this helps.
Terry
Terry,
This makes PERFECT sense to me! Sometimes the correct diagnosis can be tricky on these cars! :-)
This is a very good example of careful interpretation of test results needed on these cars.
With the engine off, the cooling system would hold the pressure of a test pump (up to 18 psi), but while the engine was running under load, combustion gases would leak from a combustion chamber into a coolant passage causing the coolant to flow into the overflow bottle.
This is EXACTLY what was happening on my 02 Civic LX. I pulled the head, measured warpage, shaved by a local machine shop, reassembly with OEM gaskets.
The engine has been purring like a kitten since last Fall, with excellent starting & idling, improved gas mileage, more power.
Tim
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