BN6 Temperature Issue

[BN6_2197]

During my last ride I observed high water temperature while my car was standing with running engine e.g. in front of traffic lights. The temperature went up to 212 F or even higher. While driving and heater turned on the temperature was normal (around 192 F). I never observed this before. Typically the water temperature was around 192 F without heater turned on and it only went up a little bit while standing with running engine.

Any idea where to start the analysis?

Chers,

Volker

 

[Keoke]

How about the fan belt is it old glazed and possibly slipping?

 

[BN6_2197]

Keoke, I will check. Might there be an issue with the thermostat as well?

 

[pkmh]

I did a quick research on the removal of thermostats, in general. I see where it is mentioned it is not necessary to have a thermostat unless you drive in a cold climate and therefore, want to keep the engine warm and for heating the interior. Because I also have this problem of the temperature rising on warmer days and as does BN6 and others, is it not such a bad idea to remove the thermostat during the hot weather?

Paul

 

[Mert]

Leave the thermostat in at all times. It controls more than just the temperature. The only issue you might have is thermostat you have might not be the correct one for a BN6. Also you might want to install a Texas fan (6 blade). And prior to all the above, conduct a full system radiator flush to include the block. Then reinstall everything. This had happened to me with my BN7. I corrected it by doing what is stated herein. Good Luck..

 

[DerekJ]

The thermostat doesn't control the temperature of the engine. All it does is open at a set temperature. To run efficiently an engine needs to get up to temperature as soon as possible so the thermostat blocks water to the radiator to achieve this. In cool climates you need a higher temp thermostat and vice versa.

The problem is not the thermostat.

 

[bighealeysource]

Had a BN6 and added a Texas Cooler fan but what made the difference when stuck in slow or non moving traffic or at a light/stop sign was the addition of a pusher fan. Easy install and you can get a good quality fan from the typical auto parts stores for far less than the ones sold by the LBC vendors, and usually same brand. My BN6 would always run about 190 and go up like Volker's until I put that on.

 

[TimK]

i had a similar symptoms and installed a BCS shroud (Kilmartin) and BCS 6 blade fan. Still would overheat on highway. This was a sure sign the radiator was the problem. Took it to a local radiator shop. They took the top tank off and showed me that 1/3 or more of the tubes was clogged by a clay like substance. I had neglected regular flushing. Replaced the core with one with higher density fins and problem solved. Also I had gotten a BCS thermostat with proper sleeve to close off the recycle port. All of these things resulted in perfect cooling under all conditions in hot weather.

 

[RDKeysor]

Like the Jedi Knight, I'm a BN7 owner and have worked to counter the cooling issues. A bit of that has appeared in this forum. Interestingly, early on I took my radiator to a place recommended by another club member and had it recored. The proprietor told me that my radiator had been hit at some point, and I recall that rusty water spilled out of it when it was removed. I had what was said to be an improved core installed and was surprised that the tendency to run warm didn't seem to have been reduced at all. Though it is common in Florida to run these cars without thermostats and with the heaters valved off, I am convinced that it is best to run a thermostat. I use a 160 degree thermostat with the Moss bypass blocking tube. I have a Texas Cooler installed by the PO, a shroud around the fan that I created, and an overflow tank. I also recently shimmed the bottom of the radiator away from the frame member behind the bottom tank, as described in a previous post. My car will get quite warm when stopped at traffic lights if the ambient temperature is in the '90s, and I have seen it reach toward 230 degrees when at a stop. I have yet to have any boil over, however. I think cockpit heat and toasty coolant temperatures are just part of owning these beautiful cars.

 

[steveg]

I removed the thermostat and cover and tested the coolant temp next to the sender with a couple of different tested meat thermometers. My temp gauge would show 20+ degrees more than the thermometers. I pulled the needle off and re-attached at the proper temp reading. Now even in 90 degree weather it always runs under 190. Problem solved!

 

[BN6_2197]

steveg, concluding from your post: it also might be an issue with the gauge or its sensor, isn't it? Can I remove the thermostat and cover without draining the cooling system? In the workshop manual it is said that I have to.
By the was, my fan belt seems fine

 

[RDKeysor]

I've verified the temperature's at my radiator and at points on the engine with a hand-held thermal gun, so I know my temperature gauge is reasonably accurate. Very interesting to run the laser around the radiator, block and other components to check the temperature. With a 160 degree thermostat rated at 7 lbs., my car's cooling system would require a temperature of about 230 degrees to boil. I've never known that to happen. I think the thing that concerns most of us is the lack of a cooling reserve in some of these cars, as they seem to suffer disconcerting temperature spikes when you slow in traffic or get held up at a traffic light. Mine, as I have reported, is very sensitive to the ambient temperature, and down here that's pretty hot.

 

[steveg]

Very little coolant is lost on removing the thermostat cover. I used a turkey baster or drained a couple of quarts out of the radiator drain tap into a clean pan. For safety, loosen the generator so the fan doesn't turn. I also have the Harbor Freight temp gun, but thought it was more accurate to measure the actual coolant temp adjacent to the sender with multiple thermometers.

Earlier models with the sender in the radiator would be even easier, as you'd warm the car up with the radiator cap off, then measure the temp of the coolant in the top of the radiator near the sender.