Two head gaskets?

[sainthonore]

Thanks a lot for the extra info which I'll definately heed.

[woolfie1948]

I would be very interested to be updated on how you get on.
Jonathan

[woolfie1948]

Any further progress to report?
Jonathan

[srs4164]

Hi,

New here and just tried to PM this directly to 940_Turbo but couldn't as I haven't sent 30 messages yet, so hopefully he'll see it here!

I've read an old post that you replied to wherein you talk about B30s silting up in the rear of the block, causing it to run hot. I suspect this is the case with mine as I've done everything else to try to correct the fact that my temperature slowly creeps towards the red, especially when I'm idling at a stop.

I've tried multiple thermostats, replaced the water pump, confirmed with a radiator shop that my radiator has no blockages, tried multiple sensors, flushed the system with radiator flush additive, gotten new OEM caps for the radiator and overflow tank and checked my compression (which was in spec) even though there were no signs of headgasket failure either in my oil or coolant. The timing is right on 10 degrees BTC. I'm not losing any coolant. I've even confirmed that the voltage stabilizer (for the fuel gauge and temp. gauge) and the gauge itself are working correctly. With all that, the coolant has been replaced multiple times within the last 2 months and I'm using Zerex G5.

With an IR thermometer, I was able to see that there is a hot stop (as high as 234 F degrees) at the rear of the block where the rear head bolt is, which is only a few inches from the sensor for the temperature gauge. Is it possible that this hot spot is effecting the sensor and that my car isn't really getting close to overheating though the gauge is almost in the red?

While all of my '71 164s (the most recent of which I owned 25 years ago) had a drain **** by the oil filter, the '72 doesn't, so I can back flush it there. I did try flushing it out through the sensor hole and did seem to get some silt out through the bottom radiator hose, but it did not rectify the situation.

Do you think its likely that my block is silted up? If so, is there any way to clean it out without having to pull the head?

Any feedback you can give me would be greatly appreciated as I really am at a loss as to what to do next. At this point, I keep the problem in check by keeping my heater control valve wide open, but I'd really like to get this taken care of, especially if this is going to cause a problem for my rear cylinders! It'd be nice if I could have the possibility of using my AC with summer approaching as well.

Thanks for taking the time to read this!

Stan

[Derek UK]

Very sadly, Peter, 940 Turbo is no longer with us. (RIP)

Comments have been made on other forums that the tapered tube that runs front to back in the head can get blocked towards the back and this obviously reduces the coolant flow. You have to remove the front and rear frost plugs to get it out so it will mean head off to get to the rear one. If you post your email addressed (disguised of course) I will send you some pictures that are on the Yahoo 1800 forum You might be a 164 owner but join it! It can be useful for 6 pot owners too. If anyone here has any experience in the tubes removal please post.

[srs4164]

Derek UK,

Thank you for the unfortunate update regarding Peter (940 Turbo). He seemed to be someone who was not only very knowledgeable, but also very happy to help others. Something quite admirable.

Stan