SL500 overheating

LeeMc

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I'd like to start with thanking everyone for all the great info I have received from here. I have an issue with a newly purchased 05 SL500/230. Someone was having issues with it, I bought via auction, salvaged as flood. But NO sign of any flood. The cooling fan was missing. Since I have replaced the fan, water pump, and thermostat. At first the temp gauge on the dash didn't read anything and the temp caution light was on, The dash blinked a coolant alarm. I drove it yesterday and the alarm went off and the gauge started working., The fan comes on, But the temp continues to rise. It climbs till I start to lose antifreeze from the lower hose area. It would level off just over the 50% mark on the gauge, then start back climbing. I plan to go back thru all the hoses next, but I'm missing something,. If I have flow, and the fan is running, I'm not sure why it would overheat. It will run hot at an idle, or driving. Any thoughts on this would be much appreciated. After this I can work on getting rid of the ABC, and brake alarms. (I have replaced all the pads and sensors already).
Thanks in advance....Lee
 

ernieh

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I think the next stage is to consider if the cylinder head gasket is leaking. A first check would be to leak test the cooling system and see if there is a pressure drop during the test.

Ernie
 

ELGRINGO

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As above carry coolant pressure test, and head gasket test. car needs to go on a star machine, if suspected flood damage could have had water ingress to front sams.
 
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LeeMc

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Is the pressure test something I can do without taking it in to the dealer? I just ran it at idle just now. It climbed to 60 degrees or so and the fan cycled on. Then it climbed to 90 and leveled off. I did find a leak. It's around the top of the radiator on the drivers side. I can't tell exactly until I can take a few things apart. I'm playing with this thing after getting in from work at night and it will be Sunday before I can tear in to it. I did just replace the temp sensor that is next to the thermostat . The old one was rotten, so it may have been a bit of an issue. Here's my biggest concern now. The fan cycles off. It is running 90 degrees, and I have the AC running, and it doesn't come back on.. I suspect that if I locate the leak, and the fan runs at that temp., I may be ok....???
Thanks again for any input.
 

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Is the pressure test something I can do without taking it in to the dealer? I just ran it at idle just now. It climbed to 60 degrees or so and the fan cycled on. Then it climbed to 90 and leveled off. I did find a leak. It's around the top of the radiator on the drivers side. I can't tell exactly until I can take a few things apart. I'm playing with this thing after getting in from work at night and it will be Sunday before I can tear in to it. I did just replace the temp sensor that is next to the thermostat . The old one was rotten, so it may have been a bit of an issue. Here's my biggest concern now. The fan cycles off. It is running 90 degrees, and I have the AC running, and it doesn't come back on.. I suspect that if I locate the leak, and the fan runs at that temp., I may be ok....???
Thanks again for any input.

Fan should not cycle on at 60°. 90° is probably where your new thermostat opens. Fan should only cycle in when the aircon requires it or when you hit close to 100°. Get your leak attended to and all might be well. Take care not to get to 100° until leak fixed as you won't have any pressure to stop boiling.
 
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LeeMc

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Thanks much.. I will try to locate the leak in the morning, If I'm lucky that will take care of things. I thought it was odd that the fan came on so early, then was not coming on at 90 degrees,,??? So is 90 about the normal temp for that vehicle? I've had 3 in the past, but I never really had any repair issues with the others. I knew I had my hands full with this car. My others were new, to maybe 40k miles. This one has 107k on it.
Thx again for the info. I will update tomorrow.
 
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LeeMc

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The upper hose seems to be the leak. I pulled the hose and I have ordered the replacement. I can't find a crack in the plastic elbow, but I'm hoping that's the problem. If not then it's the plastic coupling that mounts in the radiator. If that's the issue I suppose I will be buying a new radiator. I don't think that part can be changed..???
I planned to buy an inexpensive pressure test kit, once the hose is replaced. What pressure should I expect it to hold? Should I let it sit for a while ? Is there a specific pressure it should hold for a certain length of time.??
Thanks again for any advice.
 

television

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If the car has been flood damaged, you should look in the passenger side sill boxes, You have the engine CAN plugs terminating there, and water here will give nonsense implausible faults. this will included the ABC and SBC.
 

oigle

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The upper hose seems to be the leak. I pulled the hose and I have ordered the replacement. I can't find a crack in the plastic elbow, but I'm hoping that's the problem. If not then it's the plastic coupling that mounts in the radiator. If that's the issue I suppose I will be buying a new radiator. I don't think that part can be changed..???
I planned to buy an inexpensive pressure test kit, once the hose is replaced. What pressure should I expect it to hold? Should I let it sit for a while ? Is there a specific pressure it should hold for a certain length of time.??
Thanks again for any advice.

When testing, pump about 15psi into the system and leave it for half an hour. Should hold that pressure if no leaks.
 
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LeeMc

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Thanks guys, Very much appreciated..
Hey, excuse my ignorance, but I don't know what a sill box or CAN plug is. :D
 
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LeeMc

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I googled it. It's dry. I have yet to find any sign of flood. I think someone just wanted it scrapped out. It sat at a salvage yard for two months, and it came to me with ZERO smell, or anything...?
 

television

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Any water in the sills could sit there for a long time, the CAN communication network caries all the engine information. The passenger seat should be lifted out and the carpet lifted, then the plastic lids removed from the trunking to see the state of the CAN connectors.
 
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LeeMc

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OK, I have to have that seat out anyway, as the airbag light is on. From what I've read this is usually the connector in the passenger seat.
I've replaced the brake pads and pad sensors, but can't seem to get rid of the brake light either.
I've noticed that while running, and for a minute after I shut it off. There's a pulsing sound from what I believe is the hydraulic pump. It was low on fluid when I bought the car. I filled it, and I see no leaks. But the pump sounds like it is cycling on and off; trying to build pressure. The top and roll bar work fine, once I got the fluid added. I'm sure it's trying to do something with the leveling. It sits level. If I hit the button to raise it, it will raise. Not necessarily right when I push the button tho. ???
 

television

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You will have to check the connection in the sill, with just the heater box drain blocked the sills will fill with water and everything becomes implausible.
 
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LeeMc

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I changed my lower hose and I still have a leak at 90 degrees. Appears it is the plastic coupling that comes with the radiator. So now I have a radiator on order. I pulled the old one out. It was shockingly easy. I went ahead and ordered the lower hose being that that's all that's left not new. Hopefully I'm about done.
 

Philedge

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OK, I have to have that seat out anyway, as the airbag light is on. From what I've read this is usually the connector in the passenger seat.
I've replaced the brake pads and pad sensors, but can't seem to get rid of the brake light either.
I've noticed that while running, and for a minute after I shut it off. There's a pulsing sound from what I believe is the hydraulic pump. It was low on fluid when I bought the car. I filled it, and I see no leaks. But the pump sounds like it is cycling on and off; trying to build pressure. The top and roll bar work fine, once I got the fluid added. I'm sure it's trying to do something with the leveling. It sits level. If I hit the button to raise it, it will raise. Not necessarily right when I push the button tho. ???

You're seem to be talking about lots of different systems here that do completely different jobs. If you can hear a pump running after you shut the car down then that could well be the SBC brake unit which is at the front right of the engine bay. If the noise is from the boot then likely to be the PSE pump. The roof and roll bar have their own hydraulic pump in the boot that only runs when the roof/rollbar is operating. The suspension raising and lowering is done by the ABC pump that is engine driven so wont be running after the engine is stopped.

Can you tell where the running noise is coming from and be more specific where you added the "hydraulic oil"?
 
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LeeMc

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I added hydraulic fluid to the pump in the trunk. That also appears to be the noise after I shut the car off. I even noticed it while sitting at a red light. I could hear it cycle on for 3 seconds, then off for 3 or 4. If it's running like that when the top or roll bar are not in motion, I assume it must be for the leveling of the car .??? Is it maybe trying to raise it a little, ?? If I press the button by the shifter to raise the vehicle, it wont immediately raise. If I move it some it will eventually raise up. I would just shut all that off if I could. I feel like this pump cycling on and off will be leading to future problems. ?? I wish I could be more specific. I thought that hydraulic pump controlled the leveling, as well as the top and roll bar.
 

television

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Something not right here, the roof pump is siting on the PSE pump, the roof pump never makes a noise unless you are opening the roof. It will be the PSE pump that you heard running.
 

ajlsl600

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Something not right here, the roof pump is siting on the PSE pump, the roof pump never makes a noise unless you are opening the roof. It will be the PSE pump that you heard running.

malc , wots that then ? very small leak in the pipework ,like under the seat or in the boot ? (lock ) should fuse not eventually blow, unless its been changed for a higher rated fuse ?
 

Philedge

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I added hydraulic fluid to the pump in the trunk. That also appears to be the noise after I shut the car off. I even noticed it while sitting at a red light. I could hear it cycle on for 3 seconds, then off for 3 or 4. If it's running like that when the top or roll bar are not in motion, I assume it must be for the leveling of the car .??? Is it maybe trying to raise it a little, ?? If I press the button by the shifter to raise the vehicle, it wont immediately raise. If I move it some it will eventually raise up. I would just shut all that off if I could. I feel like this pump cycling on and off will be leading to future problems. ?? I wish I could be more specific. I thought that hydraulic pump controlled the leveling, as well as the top and roll bar.

The pump in the trunk is only for opening the roof and moving the roll bar. The ABC hydraulic suspension pump is on the front left of the engine and is combined with the power steering pump so 2 pumps in one- a tandem pump. This pump does the levelling.

As Malcolm says if the noise is coming from the trunk its likely the PSE pump which sits under the hydraulic pump you topped up. This is a pneumatic pump that powers the central locking, boot locking, massage seats, fuel flap lock and internal compartment locks. Are all the above working ok?
 
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