Chronic Overheating Probs

[car noob]

Ever since I've had my 66 mustang it has ran hotter than I'd like, I've done small things hoping that it was just something simple but it was all to no avail. Many of the small things that I have done over the years have been to switch over to a direct drive fan, install a fan shroud, new hoses, high flow waterpump, new thermostat, and just recently a new 4 row radiator. The only things that I can think of that I still need to do is that the fan is only a 14" unit, and I have not installed the shroud with the new radiator yet as it requires different brackets and I haven't gotten around to modding the 3 core ones yet.

Anyways is there anything blatantly obvious that I am missing here? The car ran dead center when going on my backroad trial but as soon as it got near traffic the temp crawled up almost till it was pegged. I know this is denotes an airflow problem (low engine speeds/in traffic) but I've also noticed that after the car starts to run hot it takes forever for it to get back the temp. back down, and never gets it back down in the center. Is that typical?

 

[Hack]

Mounting your shroud should make a big difference.

The temp should go down quickly if you get out on the interstate, however. How hot was the outside temperature when you got up to speed and the temp didn't come down?

Do you know what size the cylinders are? This is outside of my experience, but I've heard that rebuilt engines run hotter. As you go to larger and larger overbores, the engine will run hotter.

 

[car noob]

It was probably low 80's/high 70's when I took her out. I never got onto the interstate, mostly 30-40mph but constant speed once I was able to get out of traffic. The temp would come down a little, but would never get back to where it was before I hit the traffic and stoplights

The engine is a 289 that was rebuilt december of 01 with a .03 overbore.

 

[Hack]

30-40 isn't that fast. IMO, you should get the shroud on it and try it. You should be ok.

 

[Ronstang]

I thought the shroud was already installed. Have you bothered to check the tune on the car? If you timing is too retarded it will run hot and never cool down like you describe.

 

[Hack]

The only things that I can think of that I still need to do is that the fan is only a 14" unit, and I have not installed the shroud with the new radiator yet as it requires different brackets and I haven't gotten around to modding the 3 core ones yet.

Ronstang, good info on the timing. I didn't know that. That's a good one to file away.

 

[Ronstang]

Ah, I missed the didn't install the shroud with the NEW radiator....

 

[car noob]

The fan was installed w/the three row and I didn't really notice a difference with it in. Once I modify the three row brackets to fit with my 4 row radiator I'll be reinstalling it, I just mentioned it so that I wouldn't get 8 replies saying for me to get a shroud

The timing is a good idea, and noting my screen name, I am a total newbie to cars and honestly do not know where I would start to check on timing or how to adjust it

 

[Hack]

On timing, it's not that hard. If you purchase a timing light and follow the directions that come with it, you should be good. Heck, I can do it and I'm pretty slow.

You just hook it up to the no. 1 spark plug, aim it at the timing mark on the front of the engine (crank), and rotate the distributor to change. Edit: obviously while the engine is running.

You could take it to a shop, but little adjustments like this are part of the fun of having an older car.

 

[car noob]

obviously while the engine is running.

LMAO This made my night

*Runs out Buys timing light*

*stares at non-running engine for 3 days*

*dies from starvation*

 

[Ronstang]

To modify those shroud brackets you can simply take some 3/4 inch square tubing and make spacers and use longer bolts....the bolt goes thru the square. or round for that matter, and you can keep trimming them till you get the length just right.

A little tip about shrouds. Lay the fan on it's face and measure up to the back part of the fins that is turned up to determine the "depth" of the blade. You want 50% of that depth outside the back of the shroud for efficient operation. Even if you have to make a new shroud or modify the one you have this is an important thing to do IMHO. I built a custom made simply shroud for my Shelby out of a band of aluminum and had 50% of the blade sticking out the back (I read this somewhere many years ago) and the temp dropped an honest 15 degrees with no other mods.

 

[Hack]

LMAO This made my night

*Runs out Buys timing light*

*stares at non-running engine for 3 days*

*dies from starvation*

LOL! The thing is, I wrote this because I'm stupid, not because I think you are. I can picture myself not being sure how to do it.

 

[Ronstang]

Oh, BTW, check the vacuum advance too because if it is not working properly it will also cause the retarded timing affect I spoke of earlier.

 

[car noob]

Oh, BTW, check the vacuum advance too because if it is not working properly it will also cause the retarded timing affect I spoke of earlier.

Once again, I'm completely clueless on how to do this sort of thing, would I just hit the throttle and make sure that my distributor advances itself

 

[Ronstang]

Yes....rev the car and see if the timing advances. But there is some mechanical advance in the distributor so it can advance but still not be advancing far enough. An easier test is to disconnect the hose from the advance unit and plug it and then hook a section of hose to manifold vacuum (hidhest at idle) and with the timing light pointed at the crank hook the temp hose up to the vacuum advance and see if the timing goes up about 10 degrees or so.

 

[car noob]

^I had to think about what you said for several minutes but I think I've finally got it figured out, hook up the advance mechanism on the distributor to the intake manifold and this will increase the vacuum the distributor see's and bump the timing?

 

[Ronstang]

You will simply be using the hose hooked to manifold vacuum to actuate the advance mechanism while you are watching with the timing light is all.....unless you have a hand held vacum pump or you can suck really hard

 

[68GEETEE]

http://www.gofastforless.com/ignition/advance.htm


The above link may be helpful. My car constantly ran hot, and I changed every coolant related part you could think of. Wound up that the previous owner didnt have the distributor installed with #1 at top dead center, so the timing was always off, and caused the hot temps. I re-installed the dist correctly, and the problem disappeared.

 

[car noob]

Thanks for the link, I'll give it a read after finals week is over and I have some time that I can spend fooling around with my car. To be honest I tend to believe that the distributor is set up properly as it was last touched by the same people who did the rebuild and they seem to know their stuff. Of course the last time it was tuned up was a long time and a state ago as I drove my car to college so it saw a good drop in elevation and temps

 

[car noob]

Yesterday I picked my mother up from the airport, the car was running mildly warm but nothing major. My mom of course asks if she can drive and I say "of course" with the caveat that it was running warm, she then proceeds to put around 10-15mph throughout this town looking for a car rental place that specializes in higher end cars (Boxters, M-coupes, et cetera) and finally I had enough when she was going to try and turn left across three lanes of traffic. I asked her to get out so that I could drive from then on, she asks "Why?" Then no sooner than she had asked the car dies

Anyways due to the severity of the problem and the distance from my place I didn't want to try and limp my car home so I had the thing towed to a mechanics...I hate having to give my problems (especially my car) to someone else