Car overheating and radiator light on

[Dopamine]

My car overheats fast. Additionally, I opened up my radiator cap just after 1-2 minutes from starting up and a lot of coolant bust out everywhere. My radiator light comes on as well (I never knew supras have a radiator light). Also, where is the sensor located for the radiator light? What can be the possible problems and solutions?

 

[gaboonviper85]

You have a blown headgasket...time for major repair! Nothing you can do other than properly fix the motor...good luck and have fun!

 

[Supracentral]

You have a blown headgasket...time for major repair! Nothing you can do other than properly fix the motor...good luck and have fun!

Possible, maybe even likely, but not as certain as you're making it sound..

My car overheats fast. Additionally, I opened up my radiator cap just after 1-2 minutes from starting up and a lot of coolant bust out everywhere. My radiator light comes on as well (I never knew supras have a radiator light). Also, where is the sensor located for the radiator light? What can be the possible problems and solutions?

The sensor is located in the overflow bottle.

Sounds like any one of the following:

• Major air bubble in system creating hotspot/steam flash over (see below).
• Obstructed/kinked hose or obstructed radiator.
• Bad thermostat.
• Bad H20 pump.
• Blown head gasket.
• Cracked/warped head.

It's a simple system. Water flows through the block and picks up heat, passes through the radiator and sheds it. A thermostat controls when it happens, a water pump provides the motion, the cap relieves pressure if it gets too high. Works just about the same on any car. So look at the system from that perspective.

If the water isn't circulating, or if there's an air bubble, you'll get a hot spot. Coolant will flash over into steam in that location, causing a sudden pressure increase as the water expands into steam. This blows coolant into the overflow bottle, which in turn blows it out on the street.

Unfortunately, the last two items in the list above will have very similar symptoms, as the effect is usually that one or more cylinders will be pushing the compression stroke into the water jacket, causing a system overpressure. This also blows coolant out the overflow, etc, etc.

Stop running the car and locate the problem.

 

[csr ma71]

Mine was because I bought a radiator from 1-800-radiator and their end tanks was finger loose. I took the radiator out, tightened both sides down and no more/lesser overheating and no more leaks.

I also bought a rad cap from Toyota and it malfunctioned, the Autozone one was keeping temps better than the Toyota one.

 

[soc chaos]

So I have similar problem. I just dropped a jap engine in and after about 350 miles of babying it I gave it a little power the other day and I received a few problems for it. The alt belt loosened up, clutch cylinder started leaking, and I over heat if I run anything over 70ish mph. Fixed the belt and did a quick run of holding 80 and it still started to over heat not as bad but it still did any ideas? The temp goes up if I let off the gas and seems to go down a little when I start giving it gas again.

 

[Dopamine]

Possible, maybe even likely, but not as certain as you're making it sound..



The sensor is located in the overflow bottle.

Sounds like any one of the following:

• Major air bubble in system creating hotspot/steam flash over (see below).
• Obstructed/kinked hose or obstructed radiator.
• Bad thermostat.
• Bad H20 pump.
• Blown head gasket.
• Cracked/warped head.

It's a simple system. Water flows through the block and picks up heat, passes through the radiator and sheds it. A thermostat controls when it happens, a water pump provides the motion, the cap relieves pressure if it gets too high. Works just about the same on any car. So look at the system from that perspective.

If the water isn't circulating, or if there's an air bubble, you'll get a hot spot. Coolant will flash over into steam in that location, causing a sudden pressure increase as the water expands into steam. This blows coolant into the overflow bottle, which in turn blows it out on the street.

Unfortunately, the last two items in the list above will have very similar symptoms, as the effect is usually that one or more cylinders will be pushing the compression stroke into the water jacket, causing a system overpressure. This also blows coolant out the overflow, etc, etc.

Stop running the car and locate the problem.

Thanks for the help everyone. I already replaced the thermostat and water pump. I found that I had the first problem on your list. I had air in the system and I didn't refill enough coolant to the proper amount as well. It now "seems" to do fine (on the streets that is).

Whenever I hit around 70mph or more on the freeway, my car starts to overheat. What can cause this? Could it be the fan shroud? My fan shroud only has the upper portion left; the left, right, and bottom portion of my shroud is gone.

Once again, thanks for all the help!

Edit: I'm having the same exact problem as you soc chaos.

 

[soc chaos]

Yeah hopefully someone will know what it is, I am on toyota nation and no one has said anything there either so I guess we play the waiting game! Ok I just noticed you already replaced the water pump so yeah! Do you have a good rad cap on?

 

[Dopamine]

Yea my radiator cap is working fine. The only thing I can think of is my fan shroud. Also I put in another fan because my old one was messed up. I noticed the fan that put on is a tiny bit larger in diameter compared to my old one.

 

[ben1984j]

So I have similar problem. I just dropped a jap engine in and after about 350 miles of babying it I gave it a little power the other day and I received a few problems for it. The alt belt loosened up, clutch cylinder started leaking, and I over heat if I run anything over 70ish mph. Fixed the belt and did a quick run of holding 80 and it still started to over heat not as bad but it still did any ideas? The temp goes up if I let off the gas and seems to go down a little when I start giving it gas again.

Those JDM engines aren't all they're cracked up to be...they're supposedly "low-mileage" and all but many people have had problems with them. If you put one in without tearing it down and inspecting it (you did say you "dropped it in") then it's really hit or miss if it's a decent engine or not. Overheating can have several causes, ranging from minor to major problems (exactly like what Supracentral said above) but don't rule out the major...not to be negative at all but I wouldn't just trust a Japanese engine to be good.

 

[ben1984j]

Thanks for the help everyone. I already replaced the thermostat and water pump. I found that I had the first problem on your list. I had air in the system and I didn't refill enough coolant to the proper amount as well. It now "seems" to do fine (on the streets that is).

Whenever I hit around 70mph or more on the freeway, my car starts to overheat. What can cause this? Could it be the fan shroud? My fan shroud only has the upper portion left; the left, right, and bottom portion of my shroud is gone.

Once again, thanks for all the help!

Edit: I'm having the same exact problem as you soc chaos.

What about your radiator? Is it the original one? If so then it could be your problem...there's no way a missing fan shroud could cause your cooling system to fail.

 

[Dopamine]

What about your radiator? Is it the original one? If so then it could be your problem...there's no way a missing fan shroud could cause your cooling system to fail.

Yes it's the original radiator. What's wrong with the original one? Visually, it looks good.

Thanks.

 

[ben1984j]

Yes it's the original radiator. What's wrong with the original one? Visually, it looks good.

Thanks.

Nothing is wrong with it necessarily, but every time I've read about someone having a clogged radiator, it was the original one. Even if it's not the sole cause of your overheating problems, your 20-year-old stock radiator sure isn't helping the situation. Especially considering the issues you're having I would replace it at this point; there's a chance your radiator might be "fine" but it's still well past its prime.

 

[Dopamine]

Nothing is wrong with it necessarily, but every time I've read about someone having a clogged radiator, it was the original one. Even if it's not the sole cause of your overheating problems, your 20-year-old stock radiator sure isn't helping the situation. Especially considering the issues you're having I would replace it at this point; there's a chance your radiator might be "fine" but it's still well past its prime.

I'll replace my radiator when I get my next check. However, are there any other possibilities as to why it overheats on the free way?

If not, I guess I have to replace my radiator and get a few fan shroud. Additionally, has anyone tried Redline Water Wetter? They claim to reduce temperature by 20%.

Thanks.

 

[soc chaos]

Hey Dopamine how is your lower rad hose? I was reading some of the stuff... "Sometimes a lower radiator hose will collapse under vacuum at high speed and restrict the flow of coolant from the radiator into the engine. This can happen if the reinforcing spring inside the hose is missing or damaged." ...... and I recalled my lower hose did kind of seem squishy in one part of it so that might just be it!! I am going to order one and switch it I will let you know!

 

[Dopamine]

I just recently purchased my car, so I'm not familiar with all the parts on it. However the radiator itself is not the stock one that's 10+ years old. It seems fairly new. I'm assuming and hoping it's just my lower radiator hose too. I'll check out my lower hose tomorrow and let you know if there's also a squishy spot or something.

Edit: I checked out a friend's lower radiator hose that he bought brand new and I didn't see a spring inside of it. Where is this reinforcing spring located inside the hose?

 

[soc chaos]

On the hose I just bought it also doesnt have a spring in it! I dont know if they skipped out on it or what but I am thinking about ordering the performance hoses for like 25$ more! If interested here you go

 

[ben1984j]

Whoever wrote about this "reinforcing spring" was probably just referring to something in the composition of the hose...I've never heard of a lower radiator hose, or any hose for that matter, having an actual "spring" inside of it. You'll be fine with a normal radiator hose. "Squishy spots" happen because of age not inadequate hose construction. My lower rad hose even has one of these squishy spots but it's way old, possibly even the original...and is still functional...

 

[ZoomZoomZoom]

Follow Supracentral's advice! Coolant type is not going to "solve" this issue. Overheating is a serious threat to the 7m engine, be very careful. I had overheating issues with my car when in mountainous country, or on the freeway for long periods of time. I don't know what all the previous owners did, so I overhauled the whole thing at once instead of piecing it. That way I know I have a new coolant system. I replaced radiator (went with alum), hoses, thermostat, radiator cap, and coolant reservoir. Ok, the reservoir is a bit excessive, but my old one was so filthy it made it difficult to read. If you are replacing the radiator anyways, putting new hoses on is easy. Plus, it gives you an opportunity to put the hose into the coolant lines of the block and flush it thoroughly.

Best of all, doing all this is pretty easy on the 7m. If you still have issues, you could get your coolant tested for contamination. Be aware that if it comes back negative, you may still have a bhg..

And just because you have a new water pump doesn't mean its working correctly. Rebuilt stuff is usually crap.

BTW, most supras I see at meets are missing the fan shroud.

 

[ben1984j]

Follow Supracentral's advice! Coolant type is not going to "solve" this issue. Overheating is a serious threat to the 7m engine, be very careful. I had overheating issues with my car when in mountainous country, or on the freeway for long periods of time. I don't know what all the previous owners did, so I overhauled the whole thing at once instead of piecing it. That way I know I have a new coolant system. I replaced radiator (went with alum), hoses, thermostat, radiator cap, and coolant reservoir. Ok, the reservoir is a bit excessive, but my old one was so filthy it made it difficult to read. If you are replacing the radiator anyways, putting new hoses on is easy. Plus, it gives you an opportunity to put the hose into the coolant lines of the block and flush it thoroughly.

Best of all, doing all this is pretty easy on the 7m. If you still have issues, you could get your coolant tested for contamination. Be aware that if it comes back negative, you may still have a bhg..

And just because you have a new water pump doesn't mean its working correctly. Rebuilt stuff is usually crap.

BTW, most supras I see at meets are missing the fan shroud.

This is good advice. You really don't want to take any chances here...

 

[Dopamine]

I basically replaced everything - thermostat, waterpump, radiator, and radiator cap. However, the only thing left is the hoses, so I'm hoping that's the cause of the over heating at high speeds problem. Thanks.