dswclk500

2006 CLK 500, Radiator changed out by mechanic it was cracked on the side. New radiator in place now temperature gauge on..I popped hood, and the car wasn't smoking or anything. I did touch the engine and the coolant reservoir and they were both hot, but I assume it was that way because I had just drove 20 miles. Could it be the thermostat, or could it be the temperature sensor. Please help



car still rising high
by this point the temperature rose past 120, that looks like about 130ish or 140




by this point it rose beyond what the gauge could read




red everywhere, got this warning message COOLANT, SHUT ENGINE OFF

sailorben

Thermostat is cheap enough and easy to sort out. So I would try that first. Do you know if it has been changed recently or is it still on the original? Around about now they will often fail.

dswclk500

I believe it is the original

floridawriter

Do not run your engine at all when your temp is that high. You risk warping the heads, or worse.

Did you have steam or water overflowing the coolant reservoir tank.
Did you have coolant in the reservoir tank?
Was the return hose to the radiator hot to the touch?
Did your heater blow hot air when set to the highest temp?

dswclk500

Yea I figured that, but when I popped the hood nothing was smoking or anything

sailorben

Have you an infrared thermometer that you can point at the engine block or coolant hoses to tell you what the temp is and thus see whether fluid is being diverted?

Usually when these thermostats fail, they do so in an open position. However in this case it would be as a result of it being closed.

dswclk500

Not sure what you mean

floridawriter

It may not be a stuck thermostat. Could be air in the cooling system, the system not bled properly when the radiator was installed. Could be not enough coolant in the system, could be a bad water pump, could be a leak somewhere else in the system. Was there coolant in the oil or oil in the coolant overflow tank? I wouldn't assume the problem to be the thermostat at this point.

dswclk500

Well I didn't see any leaks anywhere. Perhaps the mechanic installed it improperly?

Patton001

Did you change the rad cap?

dswclk500

Does the rad cap come on the new radiator?

Patton001

They don't typically come with a new radiator cap but I would think that a good mechanic would go ahead and put a new one on. It is worth a look see though. If you don't have a good pressurized system it will not cool properly

dswclk500

hmm interesting...thank you

floridawriter

The radiator has no cap. The coolant reservoir has a pressure cap.

dswclk500

so something as simple as a radiator cap could cause the temperature gauge to rise that high...Also could it be the temperature sensor. Because this is the highest my temperature gauge has rose but when I stopped the car and popped the hood there was no smoke or anything.

floridawriter

Is there coolant at the right level in the coolant reservoir tank now (with the car cold and not running)?
If you start the car and let it come up to temp (80c) does the heater blow hot air? Do both radiator hoses feel hot?
Do you see oil (a brown scum) floating on top of coolant in the reservoir tank? Do you see brown or tan scum on the inside of the oil fill cap?

merceBENZ

Do you suspect leaking head gaskets by any chance?

dswclk500

let me go check this out and be right back with pictures

floridawriter

It's possible, if the overheating warped one or both heads. Aluminum is very sensitive to overheating and expands and contracts due to heat and cold much more than cast iron. If would also account for a loss of coolant that doesn't show as a leak under the car.

The first step is to see what the coolant level is in the coolant reservoir with the car cold. If the coolant is at the proper level, I think a stuck closed thermostat is more likely the cause - a cold radiator return hose with the engine at 80c would support a faulty thermostat.

dswclk500

Ok so once I go outside and pop open my hood again if the temperature rises you would suspect a blown gasket?

floridawriter

Not necessarily. However, it's important that you shut down the engine if the temp rises above 100c.

MarcusF

Floridawriter is right, DO NOT let the engine run at those temperatures.

As for what it "could" be. You can toss a lot of money at a car trying to guess why it's running hot. Thermostats, water pumps, it's a long list.

Worried about a blown head gasket? Check the oil level. If it’s way high, that may point to the oil pan having oil AND coolant. Does the exhaust smell sweet? Like antifreeze? That's a very bad sign. Still want to diagnose it yourself? Look at the radiator hose on the car "while it's running" and see if one collapsed. If one did, coolant wont flow. Why would the hose collapse right after a radiator install? Because the hose is a dozen years old and was abnormally bent when R&R'g the radiator. Those are just examples of what it "could" be. Someone who knows what they're doing will find the answer pretty quickly.

If the radiator was just changed, one option is to flat bed it back to whoever installed it and let them check it out. Why? A new radiator typically has never had coolant in it. If your brand new radiator had a defect (like excess solder breaking loose and clogging half the tubes), no one would know ahead of time. Does it commonly happen? No. Can it happen? Sure. Less likely on a Behr radiator and more likely on a bargain basement brand. An infrared pyrometer will show that problem in minutes. Besides, the radiator shop can run a CO2 test – that’s something the average person can’t do at home and it will allow you to rest easy (or not) on the head gasket front.

dswclk500

I went outside and let engine run. The hood of my car was still a little hot. I touched all the houses and they were hot. I took off radiator cap, and let car run, put cap back on and let it run. The temperature gauge stayed around 80. I bagged car back to see any leaks and it looks like oil could be leaking. See pictures below







This a picture around the engine




this is the coolant tank I took the top off




another picture of coolant tank with top off




I pulled car back and looks like oil is leaking perhaps




I let engine run for a few minutes even pressed gas the temperature didn't rise over 80/90

Rudeney

I looks like radiator cap is leaking. I'd replace it. And honestly, I'd replace the reservoir, too. This happened on my C240 and a month after a new cap, the gasket between the top and bottom sections of the reservoir gave way.

dswclk500

that could cause the temperature to go up?