Rust in block...is this the end?

[d9103365]

Noticed that my 77 Cordoba (400 4BBL) has had some dark coolant for a while....had the fluid changed, and the tech told me it was a little chunky with rust. New coolant still looks rusty. The car doesn't overheat..but it does seem to run a little warm on a hot day. 100 degrees outside and the temp gauge stays right at the middle mark...

Questions:

1. Can anyone tell me what temperature the standard OEM mopar temp gauge is registering? The gauge has four ticks, one in middle two on either side, and one at the H and C marks. Also, what reading on this gauge would be considered "too hot"? Isn't it ok as long as it stays under the middle tick?

2. Obviously, I have some rust in my block but don't know how bad it is. The car runs great. I've heard different things about rust...some say to boil it out, or get evaporust to get rid of it...others have told me that you just want to leave it alone and hope that the scale doesn't break off...otherwise once its disturbed it becomes an endless problem. Some people think that it should be junked because of this...what do you think?

 

[m79ded]

The temp is O.K it should be just under the half. Put in a 160 if you want it a little cooler. I had the same issue a while back and what I did was removed the thermostat opened up the drain cock on the rad and removed rad cap put a garden hose in it and ran it for a while 30 minutes until it became clear.

Then closed the drain ran the engine for an hour or so and repeated it.

Put back coolant and 180 thermostat and all was fine.

Good luck

 

[ArtH]

Changing the t'stat will not lower the operating temp of the engine. It probably wouldn't hurt to flush the cooling system and then add new coolant along with a rust inhibitor. I would say you are running within normal parameters temperature-wise.

 

[LS-300]

I would think the rust is the freeze plugs. At that age if they haven't been replaced it would be surprising. Most of the block is thick enough that a little rust is not going to be a problem.

 

[Trashdog67]

X2 what m79ded said. It would also be wise to have the radiator 'rodded out' if you are worried about the temp.

 

[WP29440SE]

Noticed that my 77 Cordoba (400 4BBL) has had some dark coolant for a while....had the fluid changed, and the tech told me it was a little chunky with rust. New coolant still looks rusty. The car doesn't overheat..but it does seem to run a little warm on a hot day. 100 degrees outside and the temp gauge stays right at the middle mark...the half way point is normal operation

Questions:

1. Can anyone tell me what temperature the standard OEM mopar temp gauge is registering? The gauge has four ticks, one in middle two on either side, and one at the H and C marks. Also, what reading on this gauge would be considered "too hot"? Isn't it ok as long as it stays under the middle tick? if its getting over the 3/4 mark , it is HOT like 230-240* it wont be long before it pops a hose or boils over. a good 180* or 195* thermostat is what you want.

2. Obviously, I have some rust in my block but don't know how bad it is. The car runs great. I've heard different things about rust...some say to boil it out, or get evaporust to get rid of it...others have told me that you just want to leave it alone and hope that the scale doesn't break off...otherwise once its disturbed it becomes an endless problem. Some people think that it should be junked because of this...what do you think? i have had "rusty" engines that have lived a long normal life. run it a month, flush it , another month, flush it. the main reason they rust is that straight water has been allowed to sit in the engine coupled with lack of maintenance. if you dont allow the rust to build up it will be fine.