Suzuki Forums banner

1 - 20 of 38 Posts

·
Registered
Joined
·
448 Posts
Discussion Starter #1
I'm suffering from my engine overheating. When the car runs without AC, the heat gauge is slightly above the middle. But when the engine is idling, it goes to three quarters to the top. When the AC is on and I'm driving slowly, the engine overheats so bad the AC stops cooling properly and the only way to bring it back down is by turning off the AC.

I looked at the engine radiator, and found that it is quite worn out, and has so many repair scars around it, and a small coolant leakage. So I assumed the problem is from the radiator and completely replaced it with a brand new one. I thought that the problem will be gone for good, but to my disappointment, the problem was still there, exactly the same way it was before, not even the slightest improvement.

I made sure there is no leakage in the engine coolant, and the engine fan is working well. The only thing I can think of is that the AC radiator, which is directly in front of the engine radiator, is too dirty that it is blocking the air flow into the engine radiator. Any input in that regard would be highly appreciated. Is my diagnosis valid? What else can I check?

I know most of you will suggest to completely remove the AC system, but that is really not an option in our region, where the temperatures reach 50 degrees and beyond for about four months of the year.
 

·
Premium Member
Joined
·
1,862 Posts
Look into the radiator throat with the engine running. Does the fluid move? Does the fluid seem to disappear (get lower) without any visible leaks? If so, look under the rear of the intake manifold and see if you have developed any pinhole leaks in the casting. It is common.

Looking at the fluid, can you see any drops of oil floating? Chacking you oil, is tere any moisture/water on the stick? Either of these signs could indicate a bad head gasket or worse.

Also look at the back of the water pump and see if you have any leaking where the tube plugs in. That is an o-ring that can wear out.

Check your thermostat and make sure it isn't corroded shut.

Since you have already replaced the rad, so unless the connections or the drain is leaking, then you are ok there.

is that enough to get started?
 

·
Registered
Joined
·
448 Posts
Discussion Starter #3
Look into the radiator throat with the engine running. Does the fluid move? Does the fluid seem to disappear (get lower) without any visible leaks? If so, look under the rear of the intake manifold and see if you have developed any pinhole leaks in the casting. It is common.

Looking at the fluid, can you see any drops of oil floating? Chacking you oil, is tere any moisture/water on the stick? Either of these signs could indicate a bad head gasket or worse.

Also look at the back of the water pump and see if you have any leaking where the tube plugs in. That is an o-ring that can wear out.

Check your thermostat and make sure it isn't corroded shut.

Since you have already replaced the rad, so unless the connections or the drain is leaking, then you are ok there.

is that enough to get started?
Ok, is my point valid, that the AC radiator could be clogged up and blocking the air flow?

I need some help with the following, as I'm not an expert in engines:
  1. Where is the waterpump?
  2. Where is the thermostat?
  3. Where do I look for oil drops in the coolant? From the throat or the coolant reservoir?
 

·
Premium Member
Joined
·
1,862 Posts
Ok, is my point valid, that the AC radiator could be clogged up and blocking the air flow?

I need some help with the following, as I'm not an expert in engines:
  1. Where is the waterpump?
  2. Where is the thermostat?
  3. Where do I look for oil drops in the coolant? From the throat or the coolant reservoir?
Well, although the AC cooler may block alot of flow, it usually isn't to blame for that much overheating. The vehicle should not get that hot sitting still for instance. You should be able to run the engine with the AC and headlights on while sitting in the driveway without overheating (no forced airflow). It gets to 110-115 Fahrenheit during the summer here, so we have to watch out for overheating as well.

When you lean over the rad and look down at the fan belts, the water pump is what the fan is bolted to. There is also a small hole in the pump face below the pulley. This is in case the seal blows and then you have a visual indication that you need to replace the pump (you will see water leaking out there).

When you follow the upper rad hose back to the engine, the water tube that it is attached to has the thermostat directly beneath it. Removing those two bolts (that hold on that tube) will allow you to remove the tube and see the thermostat.

Look for oil droplets in the throat of the rad. Use a flashlight if you need to. If the fluid is clear/green then you are probably fine. If you see spots then there may be a problem.
 

·
Registered
Joined
·
448 Posts
Discussion Starter #5
Thanks Bill, I'll do that today. BTW, I noticed the mirrors in your two Samurais are on the fenders, rather than on the doors, how did you do that?
 

·
Registered
Joined
·
448 Posts
Discussion Starter #6
I checked the car:
  1. There are no oil drops in the Coolant
  2. There is no moisture in the oil stick
  3. Fuel pump looks very good and seems to have been recently replaced
  4. Coolant seems to be moving well.
Unfortunately I forgot to check the thermostat.

What else could it be? Only thing I can think of otherwise is the engine head and head gasket.
 

·
Premium Member
Joined
·
1,862 Posts
So in case the thermostat is corroded, how easy is replacing it? And would that mean that my thermometer is giving me a false reading?
The reading is probably correct. If the thermostat is corroded (clogged) and doesn't function correctly then your engine is not getting the coolant it needs to stay at a normal temperature. It is an easy replacement. Just get a new one, some RTV (sealant) and a new gasket.
 

·
Registered
Joined
·
448 Posts
Discussion Starter #12
Ok ok, so how does the thermostat help cool the engine? Does it increase the coolant cycle inside the engine, or what?
 

·
Premium Member
Joined
·
1,862 Posts
Ok ok, so how does the thermostat help cool the engine? Does it increase the coolant cycle inside the engine, or what?
Exactly. It controls the flow of the coolant.
Flowing too slow - the coolant doesn't get to the rad quick enough and in boils in the block.
Too fast and it doesn't get a chance to cool in the rad before it is pushed back nto the block.

The thermostat is supposed to try and keep the fluid travelling at a speed that will even out the temp and keep it at the desired level.
 

·
Registered
Joined
·
71 Posts
fan

Check fan operation. I don't have a wiring diagram in front of me right now but generally the fan needs to be on when the a/c is on.
squid
 

·
Registered
Joined
·
117 Posts
i had a similar problem and it turned out to be the clutch fan was dead and not engaging when hot, if i was you i would replace the thermostat because its only about 5 bucks and about a ten minute job and if that doesnt solve it get a new clutch fan and make sure thats working, as far as the a/c problem its just because its working the engine harder, and while idleing its not spinning so its getting it hot but while driving its air cooling, my 87 samurai did the same thing and i was starting to get worried but i just got the new clutch fan and its fine
 

·
Registered
Joined
·
448 Posts
Discussion Starter #18
Check fan operation. I don't have a wiring diagram in front of me right now but generally the fan needs to be on when the a/c is on.
squid
Yes, I checked that. It's working fine.

i had a similar problem and it turned out to be the clutch fan was dead and not engaging when hot, if i was you i would replace the thermostat because its only about 5 bucks and about a ten minute job and if that doesnt solve it get a new clutch fan and make sure thats working, as far as the a/c problem its just because its working the engine harder, and while idleing its not spinning so its getting it hot but while driving its air cooling, my 87 samurai did the same thing and i was starting to get worried but i just got the new clutch fan and its fine
I'll do that. Replace the thermostat. Gotcha.
 

·
Registered
Joined
·
193 Posts
Both the thermostat and the fan clutch are common wear-out items. Replacing the thermostat every few years is good preventive medicine. [I once got too cheap and postponed doing it and lost an engine and car -- learn from my mistake. ]
A failed fan clutch can be harder to diagnose. One symptom is that the car gets hot at idle, but cools adequately while driving. You'll have to drain the coolant and remove the radiator to access the fan clutch bolts, but it's a pretty easy repair. New fan clutches are commonly available.
 

·
Registered
Joined
·
448 Posts
Discussion Starter #20
Both the thermostat and the fan clutch are common wear-out items. Replacing the thermostat every few years is good preventive medicine. [I once got too cheap and postponed doing it and lost an engine and car -- learn from my mistake. ]
A failed fan clutch can be harder to diagnose. One symptom is that the car gets hot at idle, but cools adequately while driving. You'll have to drain the coolant and remove the radiator to access the fan clutch bolts, but it's a pretty easy repair. New fan clutches are commonly available.
How do you diagnose a problem in the fan clutch? I would imagine if the fan cannot be rotated while the engine is off means the fan clutch is in good shape, no?
 
1 - 20 of 38 Posts
Top