When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Engine overheated, coolant pressure leakage maybe normal, leakdown looks good
EDIT: I just finished performing a leakdown test and the numbers are good and I didn’t see any bubbles in the coolant reservoir. I tested the coolant pressure twice with my power bleeder and lost 3 psi in 2 minutes and 1.5 psi in 2 minutes. The Bentley manual says you shouldn’t lose more than 1.45 psi in 2 minutes so I’m not sure if I should consider this a pass. The thing is I can’t find a leak anywhere. The only two places I could check better are the bottom of the thermostat by removing the air box and the flange for the water pump. I tried checking with a boroscope and didn’t really see anything apparent though. I’m going to put it in front end service so I can check that. I also still need to run the engine with my scanner and check to see the low and high fan comes on at the right temperature. If all these thing check out, then I’d be inclined to think I have a faulty water pump but it only has 7-8k of use.
Hi all,
I’m going to diagnose what happened yesterday with an overheat on my r53. Would appreciate any advice on diagnosing the culprit. I have a Schwaben scanner that I’ll use to check that the low speed fan is turning on at 221 and high speed at 234.
The water pump and thermostat/gasket were replaced and have about 7-8k. I’m going to check for any leaks.
The coolant level is between min/max but I’m going to bleed it again. I put in a new clutch and bled the coolant and I’ve driven about 1k without any problems. But I had a look at my Bentley manual and I noticed it instructs the reader in the coolant filling section to run the engine without putting on the expansion cap back on. It says to fill it up as the level drops. I thought there was risk of coolant spewing if the cap is off? Or is that spewing a risk once it’s become pressurized with the cap on and you try to remove the cap? Thanks for your help!
I also still need to run the engine with my scanner and check to see the low and high fan comes on at the right temperature.
Or you can listen / watch for it. Ironically it helps to run the AC to get the fan to come on in high speed at idle to keep the engine cool.
Whether or not that's the issue, you can safely bet it will be someday. Mine went around 58K. It looked like all the others...
Also, if you haven't already, consider replacing the tank and cap - both notorious leak sources. "When the tank turns brown, don't leave town." Recommend metal for the tank (and anything else plastic, which is to say cheap German government-mandated recycled plastic, thanks Angela Merkel & BMW), i.e. thermostat housing and upper bleed screw and pipe, all worth the investment.
Regarding your original question, what the Bentley says is fine about running with the cap off while bleeding the system. Just don't pressurize the system and then remove the cap.
Or you can listen / watch for it. Ironically it helps to run the AC to get the fan to come on in high speed at idle to keep the engine cool.
Whether or not that's the issue, you can safely bet it will be someday. Mine went around 58K. It looked like all the others...
Also, if you haven't already, consider replacing the tank and cap - both notorious leak sources. "When the tank turns brown, don't leave town." Recommend metal for the tank (and anything else plastic, which is to say cheap German government-mandated recycled plastic, thanks Angela Merkel & BMW), i.e. thermostat housing and upper bleed screw and pipe, all worth the investment.
I hear ya about the tank. It looks like my low speed fan went at some point bc the fan runs intermittently, maybe every 20-30 seconds and for about 5 seconds. I also plugged my Schwaben scanner and noticed the low speed fan did not come on at 221F, only the high at 234F. I purchased a replacement resistor and hopefully that’s the only problem. The first time I pressurized the coolant system and lost 3psi in 2 minutes, the cap wasn’t tight enough. The second time was within Bentley’s suggest spec for coolant loss.
I have some Innovate gauges I’ve been wanting to install but I think I’m going to go the easier route with the Scangauge 3 that recently came out so I can monitor things more vigilantly.
Here’s a vid of the fan coming on/off with the AC on. I also was monitoring evaporator temp/refrigerant pressure bc I have an AC issue so those are the variables on the graph.
Regarding your original question, what the Bentley says is fine about running with the cap off while bleeding the system. Just don't pressurize the system and then remove the cap.
