Radiator doesn't like to be full

[iinoz]

I have only owned my 1991 Camry for nearly 3 months (SV21 sedan, 2.0L efi, 5 speed manual). I had the car serviced shortly after I purchased it, this included replacing the coolant, and the radiator cap. It then started leaking from the overflow reservoir. After coming home and parking it in the driveway under the car there would always be a noticeable leak of coolant on the concrete. When the car was cold I opened up the radiator to see the level, and then saw that the level had gone down noticeably, but the overflow reservoir was nearly full (way above the "full" line).

I observed this for a week or 2 and took it back to the mechanic. He pressure tested the radiator and found it to be OK. He drained the overflow reservoir to the full line marker. But after driving it again the overflow reservoir was again overflowing. I then added coolant fluid back into the radiator when the engine was cold again. It continued to overflow out of the reservoir tank when I came back home after the next time I drove it.

I went back to the mechanic and he told me not to add fluid to the radiator, but instead said to leave it. He said that the radiator/overflow reservoir had to find their own equilibrium point and that the radiator itself didn't have to be full, as long as the coolant level was above the tubes that go down to the bottom of the radiator.

I took the car to the Toyota dealer in the next town and he straight away suggested that the car had a leaking head gasket. The car itself drives very nicely, but gets appalling fuel economy.

I live in a rural area and only drive on highways to other towns in the area and longer trips to Melbourne (Victoria, Australia) which is nearly 100 miles from here. Except for 2 partial fill-ups I have never achieved over 30MPG (12.8km/l or 7.8 l/100km). The car is averaging 28.6MPG over 3131miles (12.15 km/l or 8.23 l/100km over 5038km). I drive very conservatively, observing speed limits, generally just under 100km/h (or a bit over 60 mph), on pretty good roads. No traffic jams, next to no idling

I did some research on the internet and found that a combustion leak test could be used to determine the possibility of ahead gasket leak. This test has not been performed yet.

I keep a close watch on the temperature gauge, and it stays in the normal operating range, if anything, it drifts into the lower end of the range. I have never seen the gauge go beyond the right half of the range.

So the question is:
Is it normal for the coolant level to be so low?
What is the problem?
Does it have any connection with the poor fuel economy?

See pictures below of radiator coolant level

[Jimnist]

If you see it dripping onto the concrete, then it's definitely leaking somewhere. Do you see a lot of steam puffing out the back of your car after it's warm? Have you tried going under and looked at the hoses? Could be leaking at a joint, petcock e.t.c.

That fuel economy you're getting isn't what i'd call bad. I get the same - you have to remember it's a ~20yo car.

That combustion test is just testing the coolant for gases - carbon dioxide i think. If it's present, it means you've got a blown head gasket.

[iinoz]

If you see it dripping onto the concrete, then it's definitely leaking somewhere. Do you see a lot of steam puffing out the back of your car after it's warm? Have you tried going under and looked at the hoses? Could be leaking at a joint, petcock e.t.c.

I should have mentioned it always leaks from the overflow of the overflow reservoir. I have never seen steam puffing out the back, this would indicate a very high rate of coolant loss. The loss in fluid indicated by the images I have posted are over about the last 500 miles (800km). I had the radiator pressure tested and all the joints and hoses checked by the mechanic

That fuel economy you're getting isn't what I'd call bad. I get the same - you have to remember it's a ~20yo car.

The poor fuel economy is the biggest disappointment in owning this car. A 20 year old car in reasonably well maintained condition should be able to achieve fuel economy in a range not too different from the same car just a few years old. I am getting similar fuel economy to a much larger car (1997 3.8L V6 Holden Commodore VT series):
from:http://www.drive.com.au/Editorial/Ar...eID=69667&vf=1

Fuel economy won't be great around town but on the highway, a VT Commodore can easily achieve about 9.0 litres per 100 kilometres, making it an even better bet for someone looking to cover big distances.

This car weighs about 330kg (or 720lb) more than a Camry and gets 26MPG (9l/100km) on the highway compared to 28.6MPG which I am averaging with the Camry. Note that I am quite sure the review is referring to the 4 speed Auto version, so this makes the comparison even worse for my 5 speed manual Camry.

Looking at other posts regarding the SV21 Camry (Gen2 1987-1991). People report fuel economy figures for highway/freeway use consistently in the early to mid 30's MPG range (6.5-7.5l/100km), with some reporting high 30's (close to 6.1l/100km).

I don't see how a car that is otherwise running well just can't break 30MPG. As I mentioned on the previous post I have only managed better than 30MPG for 2 partial fill ups, I have never managed better than 30MPG for when I fill up at around 1/4 full. As I said this is for driving gently on rural highways, at around and just under 100km/h (60 MPH).

If anyone has any suggestion as to the issue of poor fuel economy and if the low radiator level is a related issue. I would appreciate any comment.

[Jimnist]

Remember, when we do 110km/h the commy's are big bore 6 cyl that sit around ~2000rpm while our little 2L 4cyl is buzzing away at >3100rpm when doing 110. Not to mention, our cars have no torque over the commy so if you're overtaking, that's more fuel being used.

If you're going to be doing long drives between rural towns, you should've stuck with the Commy. Maybe you should re-consider getting another Falcon/Commy?

If it's leaking from the overflow only and the radiator level is dropping, then i can only think of(again):
1) Cap defective
2) Radiator clogged/not cooling enough so the coolant boils it all away

[71Corolla]

Owning an '87 automatic, I an offer some insight. Firstly, my car gets extremely good fuel efficiency. I've been able to get 40+ mpg on the freeway, and often 30 in the city. (these are calculated using the American gallon). Since the car was new, it has always returned very good fuel efficiency. The engine also is tuned for low end torque, the 3SFE differs a fair bit from the 5SFE in this regard. Toyota used the DOHC and 4 valves/cylinder to make the 2.0 liter engine have more low end power than most engines of the same size. Cruising at 110 km/h, the engine turns at about 2400 rpm (maybe a tick less) a Camry with a 5SFE auto will be about 2600-2700.

Your problem may be something as simple as a bad radiator cap, or you could indeed have a bad head gasket. My car actually does have a failing gasket (engine has about 405,000 km) but it is not bad enough for me to consider repairing it. My symptoms are I get some engine oil in the radiator over time. When the system is not pressurized, the oil comes in much faster. So when I do a drain and fill, I do it as quickly as possible to minimize the amount of oil getting into the coolant. Only a small amount does, and once the system is full and under the normal pressure, it hardly happens. Because of this, I don't bother ripping the engine apart even though it should be done. At this point I'm trying to get as long a life out of the engine as I can without opening it.

In your case, it's possible that a failing head gasket is causing air to be pushed into the cooling system, which eventually pushes the coolant out and into the overflow tank. A leak test would not necessarily show this, because the combustion pressure is much higher than a radiator pressure test. If you have a Lisle spill funnel, you can use it to see if air is being pushed into the coolant. Just run the engine until hot and watch for small bubbles to continually come out.

Either way, I would start by replacing the radiator cap. Only use a genuine Toyota cap, many aftermarket caps are complete trash. As for your car not getting the fuel efficiency it should, that could be many causes, hard to say. A general tune-up might help, but it may be something like a bad oxygen sensor etc. These years of Camry don't illuminate the CEL as aggressively as later years so you may have a problem but the computer is not telling you about it.

edit -- have a watch of this video, he talks a lot about what can go wrong with a cooling system it might give you some insight.

You Tube

You Tube

[iinoz]

Originally Posted by 71Corolla

Owning an '87 automatic, I an offer some insight. Firstly, my car gets extremely good fuel efficiency. I've been able to get 40+ mpg on the freeway, and often 30 in the city. (these are calculated using the American gallon).

At last someone, and an owner of an automatic Camry no less, who gets consistently good fuel economy ( I used US Gallons = 3.78 litres )

Originally Posted by 71Corolla

Your problem may be something as simple as a bad radiator cap, or you could indeed have a bad head gasket.

The radiator cap was replaced by a generic one, but the mechanic said it was all OK. I can see you mention further on that a genuine one would be better.

Originally Posted by 71Corolla

In your case, it's possible that a failing head gasket is causing air to be pushed into the cooling system, which eventually pushes the coolant out and into the overflow tank. A leak test would not necessarily show this, because the combustion pressure is much higher than a radiator pressure test. If you have a Lisle spill funnel, you can use it to see if air is being pushed into the coolant. Just run the engine until hot and watch for small bubbles to continually come out.

I'll ask the mechanic about using a Lisle spill funnel to look for air bubbles.

Originally Posted by 71Corolla

As for your car not getting the fuel efficiency it should, that could be many causes, hard to say. A general tune-up might help, but it may be something like a bad oxygen sensor etc. These years of Camry don't illuminate the CEL as aggressively as later years so you may have a problem but the computer is not telling you about it.

I took it to a Toyota dealer in the next town to have a look at, he (the service manager) recommended that the injectors be cleaned. It also had oil leaks from the spark plugs. Both of these things were done/fixed, the exhaust note sounded more vigorous at idle, but there was no improvement in the fuel economy. The Australian version of the Camry (gen 2 - SV21) has no Oxygen sensor at ALL. The Toyota dealer also tested the ECU and said it was not reporting anything untoward. When I talked to him about the radiator issue and he was quite adamant in saying the head gasket was leaking, but didn't offer any detailed explanation, after that I got a 2nd opinion from the mechanic in the town where I live, which I outlined in my first post.

Thanks for posting the video, I'll be watching it.

Originally Posted by Jimnist

If you're going to be doing long drives between rural towns, you should've stuck with the Commy. Maybe you should re-consider getting another Falcon/Commy?

If I knew what I know now either would have been a better choice, but I have always previously been happy with 4 cylinder cars.

Originally Posted by Jimnist

If it's leaking from the overflow only and the radiator level is dropping, then i can only think of(again):
1) Cap defective
2) Radiator clogged/not cooling enough so the coolant boils it all away

Perhaps a genuine cap instead of the generic one, as suggested by 71Corolla. As I mentioned the temperature gauge has never gone into the upper half of the range, I would hopefully expect the temperature gauge to go up if the radiator was clogged or not cooling enough.

[csaxon]

The generic radiator radiator cap may not be the correct pressure rating or is defective.

[Blakeman]

Did you put in the coolant or did a mechanic do it? If you did it did you follow the standard procedure and let all the air out of the engine coolant lines by running the engine for a while and adding coolant as the air bubbles make their way out?

It could be something as simple as the air bubbles are trapped in there and are pushing out through the only exit they have (overflow reservoir) and are pushing some coolant with them in the process.

As far as economy, has the fuel filter been changed and all standard maintenance been done? (plugs, wires, filters, oil, tire inflation etc)

[iinoz]

Originally Posted by Blakeman

Did you put in the coolant or did a mechanic do it? If you did it did you follow the standard procedure and let all the air out of the engine coolant lines by running the engine for a while and adding coolant as the air bubbles make their way out?

The mechanic did it a few days after I purchased the car. If it wasn't done properly I assumed it would have settled down after only a few hours of driving. This problem persists after every drive ever since (over 3000 miles)

Originally Posted by Blakeman

As far as economy, has the fuel filter been changed and all standard maintenance been done? (plugs, wires, filters, oil, tire inflation etc)

Oil and Oil filter were changed, same with coolant and radiator cap a few days after the car was purchased. Tyres are kept very well inflated (around 35 psi).
Plugs, wires and fuel filter are as they were when I bought the car.

[iinoz]

Had another talk with the mechanic. He basically transferred coolant fluid from the overflow reservoir to the radiator, I was surprised as to how easy it was to remove the plastic container. He told me to continue to check the levels of the coolant.

I also mentioned to my mechanic that the temperature gauge sometimes goes quite low during a long drive, and then doesn't come back up to the normal range. He suggested replacing the radiator thermostat. It is something I didn't take note of for the first 2 months, but have been carefully observing it lately. It was replaced today, and on a 50km (return) drive to the next town, the temperature gauge sat solidly at the 12 o'clock position after the initial warm up (previously around 10-11 o'clock position). The warm up was quicker, and even with the heater on full and one long descent, the temperature gauge didn't move, whereas previously it would plummet. I assume the thermostat was previously stuck at least partially open. Another related aspect was that previously after a long journey, the car would idle higher as if the engine was not fully warm. Now it was idling at around 700rpm at the end of the drive.

I would expect that this change would improve the fuel economy, and will report back, but my wife and I now have a new car and the Camry isn't used as often, probably have one fill-up every 3-4 weeks.

I will still be watching for the other issue relating to overflow of coolant, but as of the first drive since the thermostat was replaced there has been no change in level of the coolant overflow reservoir.

[Blakeman]

Good deal, glad you got it figured out and fixed. Let us know if the fuel economy changes dramatically.

[iinoz]

Originally Posted by Blakeman

Good deal, glad you got it figured out and fixed. Let us know if the fuel economy changes dramatically.

This Camry has become our second car, so I haven't used it much. Have driven around 3200km (2000 miles) since August (4 months), but this is more than enough to show any changes in fuel economy.

Pre-thermostat replacement fuel economy:
28.6 MPG or 8.24 l/100km or 12.14km/l

Post-thermostat replacement fuel economy:
32.3 MPG or 7.29 l/100km or 13.72km/l

A definite improvement, with the last tankful getting:
33.7MPG or 6.95 l/100km or 14.38km/l

As mentioned in the previous posts, I drive almost exclusively on rural roads at around 95km/h-100km/h very gently in 5th gear (most of the time). The tyres are very well inflated, around 37psi. Though I am pretty happy with the results, I am still jealous of others that can achieve 35MPG+ without being as careful as I try to be.