67' Mustang cooling issues

Hello everyone.

I have a 1967 Mustang that I've been working on for a couple years now and I've ran into a cooling problem that I can't seem to figure out. To start, I had the original 200ci engine sent out to be rebuilt about 4 years ago, and I put it all back together and bought a champion 3 row aluminum radiator for it. I ran into some fitment problems with hoses, but for a couple of years the car ran cool and I had no problems at all- then again I wasn't running the car for long period of time.

Fast forward a couple years and drives and I've noticed the classic problem- temp stays nice and cool while the car is moving, but gets really hot when sitting in traffic or at a stop light. I only would notice this on long drives, but now even going to some errands the car will begin to get hot.

Here's what I've done so far (and the problem still persists)
1) Thinking the 3 row radiator was too impeding of airflow, I switched back to a ACP aluminum radiator that is two row and much like the original design. I just installed it yesterday and I have to say it is much better in terms of fitment than the champion radiator. All the transmission cooling lines and original hoses fit much better.
2) Changed out thermostat for stock replacement at NAPA auto (I believe its 180* degree thermostat), changed out radiator hoses for fresh ones, radiator cap is new which is a 13lbs unit
3) Installed a new Flowcooler aluminum water pump
4) I have a B/M transmission cooler mounted at the front of the radiator, with transmission lines linked in series with the transmission cooler at the bottom of the radiator (the transmission cooler is not mounted directly on the transmission but rather on some brackets I made) It is also important to note that when I'm sitting in traffic and I put the car into park or neutral, the temperature starts to cool down once again...
5) Installed a Derale 15 inch Flex Fan Part # 19115 to replace the stock 4 blade fan

After everything I threw in the towel and actually took it to a shop in town so they could take a look at it. I explained the problem and everything I had done to it. They were nice and actually didn't charge me at all for looking at it! They ran tests on the engine to check if there were head gasket issues or something else but it came out fine. They believed that it was something with airflow through the radiator, and recommended to get a fan shroud or upgrade to electric fans. I bought a universal chrome fan shroud afterwards and attached it to the radiator, only to still come up with the same heating problem.

I'm at wits end with this problem as it's so odd. I had the car running perfectly, even taking it on a 6 hour road trip no problem so it feels like this problem just came out of the blue. I have considered electric fans instead of the belt driven fan but it looks like I have only about 1.75 inches of clearance before it hits the edge of the water pump.

Any advice?!

Thank you :roll:

Some pictures of your system would be helpful but I'll give it a shot if you can provide some adistional info. Do you remember many of the details of your engines rebuild? What is the actual temps your seeing? Does the fan shroud fit the full radiators core? How far is your fan from the shroud?

Hi there, thanks for responding- I'll try to fill in some more details!

I don't remember any details about the rebuild as it was a couple years ago and a reputable shop here in my town did all the work. All internals were gone through and replaced and the head and block was serviced and put together at the shop. No mods or anything done, as I wanted it to just be a good runner.

I don't have actual temp readings but the stock temperature gauge will get up to 3/4 full to almost 'H' pegged out depending on how long I'm in traffic for ( there has been an instance where it started to stall when I was stuck in traffic on the highway). I ended up returning the fan shroud as it didn't really do any good and I think probably made the problem worse. It was a universal piece of chrome that was 3 inches wide and only covered over the half portion like a "U" over the fan. The fan was about half in.

I'm new at posting pictures and not sure how to do it correctly on here...but here is a link to some pictures of google images.

Thanks!

https://photos.app.goo.gl/5guM2zgz5wWYZLUq9

Hi, I don't see the fan, or bolts holding on the water pump pulley. Good luck

Thank for the pictures! The reason I asked about the engine is I have had a few over the years were there was some core shift and with a block that got bored out to .060 over would over heat. I doubt that's your problem. Have you did a compression test on your engine recently? How is the tune up on your engine? Base timing can have an effect on overheating.

Looking at your pictures it looks like radiator is a fairly good fit, here are some ideas I see that need attention. The 1967 Mustangs were the first year for the big block FE 390, the front radator header was designed to handle the much larger / wider radiators to cool the 390's. The smaller radiators used with the small block V8's and 200 Six used bolt on side panels to fill in the open gap with the narrower 20 inch wide radiator I don't see these in your picture. If you don't have those Panels anymore you could make some out of some Sheet Metal or Aluminum, these help to better direct the air flow though the radiator.

With out a shroud the fan Idealy will be 1 inch from the core, of course a shroud is much better yet if it fits the full width and height of the core it then pulls air through the compleate core. In the below link is a 20 inch V8 shroud I have even used these and the V8 Radiators with the Six'es by moving the top radator hose inlet over on the brass / copper radiators, you might check if your Aluminum radator is based off the Mustang V8 Radiator measurements. I don't blame you for taking that chrome shroud back it wouldn't do anything good for cooling with shuch a poor fit. The fan diameter should also be 1 inch smaller then the shroud opening diameter and a fixed or clutch type fan needs to be half way into the opening a flex type fan needs to be 3/4 of the way into the opening. I didn't see your fan in the pictures, a 5 or 6 blade fan in the right diameter shroud do the job.

Normally the stock Thermostat is in the 192 to 195 degree range, the 180 May be ok though depending on how it's made there can be a small vent that's installed to the top of the thermostat housing. On thermostats that don't have the vent sometimes you can drill a 1/8 inch hole to accomplish the same venting. I make it a practice when changing coolant and refilling to turn on the heater to help remove all the air in the system quickly, and sometimes raise the front end or park so that the car is higher in the front. Does your car puke or loose any coolant on the ground? If it dose you could use a coolant recovery tank or go up to a bit higher pressure radiator cap. As far as the stock gauge they are ok if they are working correctly, then as long as the gauge is near the center point is real good, however anywhere within the two bracket marks it's considered normal operating range. It's also ok for it to creep up some like when climbing a steep grade or setting in traffic one thing you can do during climbing a grade is to turn on the heater for slightly more cooling capacity. Final thoughts is you could use a coolant recovery tank if your looseing any coolant. What do you use for coolant? I think with a little fine tuning you can get it to wok better, since it's cooling back down as soon as it's moving again I would focus on getting the correct fan and or plus a shroud too. Best of luck.

1967 Mustang Fan Shroud for a 20 Inch Radiator
https://www.cjponyparts.com/fan-shroud- ... /p/FANS16/

nother guy's runnin a thread on this just now. Problem is he asked a Q on a different item so we could not help till gettn to the correct Q "How can I pull my running temps down. Do I need to?" It a thread called "Help me select the right radiator fan". Ck it out for some ideas, may be?
viewtopic.php?f=1&t=81188
There are abt a doz things U can wrk with to effect running temps. The big one bubba named - proper tune.
Here's the areas:
* leaks in system; air in system
* correct shroud (fan 1/2 in/1/2 out unless 'flex', that = 3/4 in)
* coolant - mix, additives, age, cleanliness;
* water pump - operation, condition; cavitation;
* heater core - leaks, condition, it;s fan on/off;
* block - water passages;
* hoses - colapse, leaks;
* thermostat - condition, temp rating;
* radiator (sz, # rows, clean?, construction, materials - I like ol style copper)
* radiator cap - pressure rating, condition, design;
* fan (blades, design, clutch)
* flush system last yr or 2?
Too cool (below 180*F) can B a problem too.
Your pic may not help us. I'd like to see what's in frnt of the rad...2C if it's gettin some good breeze. Ur prob is at idle so it's "all on the fan" to cool @ that time. A place to "start the thinkin"~

Hi everyone,

Thanks for the suggestions. In the picture I was in the middle of removing the old cheap universal shroud so I took the fan off, hence why it is not present in the picture. Would a 5 blade flex fan be more efficient at cooling than the stock 4 blade rigid fan? I have heard from some people that the flex fans sometimes aren't as efficient at cooling with these old motors but that could all be talk. I do have the original metal slats mounted on the sides of the radiator to cover up where the larger radiator for big blocks would go so no worries there. I'm just using 50/50 percent coolant and water mixture for coolant at the moment.

The shop ran a compression test and it checked out, unsure if they checked my timing or not but I'll call to see what other tests they did on the engine.

I will buy the recommended fan shroud and see if it'll mount on the radiator, it looks like both the radiator hose outlets are on the passenger side- currently my set up has the bottom hose on the driver side and the top hose on the passenger side, but I'm guessing I can just cut out a section for it to fit correctly?

Perhaps unrelated, but I noticed I had routed my transmission cooler lines incorrectly- I had the outlet and inlet to the transmission from the coolers mixed up. Put everything in the right order...perhaps extra hot transmission oil running through the radiator cooler at the bottom had something to do with it?

Updates to come... :roll:

Yes a 5 blade flex fan will cool better than a stock 4 blade fixed fan, this is what Ford factory installed on the later model small six cars with factory equipped AC (see the below ilistration). For example that's what my 1977 Maverick 250 came with stock a 5 blade flex fan and a shroud. If you can find one of these flex fans and a good shroud it would be close to ideal. A good fitting shroud can drop engine operating temps as much as 10 degrees. Glad to hear that you have the radiator side panels installed, and that your engine compression test was good also that eliminates two possibility's. Dose your lower radiator hose have the internal spring inside to keep it from collapsing?
[image]http://1bad6t.com/Maverick/repair/images/untitled249.gif[/image]
One thing I was going to mention was about your auxiliary trans cooler lines (and it maynot be much of a factor in your current problem) but when I install these auxiliary trans coolers the lines are in series with radiator cooling lines, I also mount the cooler and lines so that they are near the bottom side of radiator core I have also mounted these cooler laying flat at the bottom edge of the lower tank or even below it and behind the radiator core mightnot be a big deal but in that way it's not adding any more heat in front of the radiators core. Best of luck

bubs: can U say if that Mav radiator is specific to the 3.3/4.1?
Did they use the bent8 radiator?
It's big...think it would fit w/o mods to the core support (no new bolt holes, enlargen 'opening')?

Yes the 200 / 250 six radiator is specific to them different top radator hose size and position from the V8's. I have also used the V8 radiators for the six'es by blocking off the top radiator hose outlet then installing the six hose outlet so it matches the six location. Mavericks got the 302 V8's early in their production (1971) so core support was already modded for them.

yeah, Mav hada bent8. Ppl may C where I'm goin w/this.

He could put the 'big motor' rad in the 'lill i6'. May B use both
oe hoses, cut in the middle, a muffler reducer and 2 hose clamps joining.
I think they might B 'wrong side' on the top though? Not sure what you mean
'block off' ?

I would remove the larger top radiator hose outlet on the V8 radiators then block that hole off with a piece of flat brass soldered over it. Then make a new hole in the right location for the smaller 6 cylinder radiator hose outlet. On one of my 1967 Mustang projects long ago "a GT fastback" that was missing the orginal 390 V8 engine (PO had blown it up) then when I bought it I also used its much larger radator by modding it some for use with a good HiPo 289 V8 that happened to have setting in my shop.

Hi all, just a quick question regarding timing as it has been mentioned on here before that it could be a determining factor as to why the engine is running hotter...what should the proper timing be on an engine like this? Also, the replacement thermostat doesn't have a hole/vent on it, so should I take it out and drill one in?

I want to stress that this cooling problem has only up until recently been a problem- like I said in my original post there was a period of time when I had the car running and driving initially after the engine/trans restoration and I didn't notice any cooling problems. I even drove it on a six hour road trip back and forth with no issues at all... and it had the stock fan and no fan shroud at all! It was stored over the winter with the occasional weekly outing to run the engine and fluids a little, and then the problems started up. So this is why I'm confused as to why the problem just sort of snuck up on me :|

Thanks again, updates soon to come as I install the fan shroud!

lalogutierrez21":1rrd2fid said:

...Thanks again, updates soon to come as I install the fan shroud!

Click to expand...

aren't U the fella who overheats in traffic, totally different problem than this 3 hr one way trip, 3 back.

Here are the compleate tune up setting for a stock 1967 Mustang 200 six.

With a stock point type Ignistion system
1. Spark Plugs are gapped at .034
2. Point gap is set at .024 to .026 for the base generic setting you would want a end up with Dwell setting of 36 Degrees for best results.

With any of the several electronic Ignistion systems available the "Plug Gaps" will be set wider this below example is for a Ford DuraSpark II, a Pertronix Ignitor and Blaster coil will be from .045 to .050, and the HEI system can be set up to .055 to .060 gap.
1. Spark plug gap for a DSII is .044
2. There is no dewel setting

3. Factory Base timing is set to aprox. 6 BTDC for manual trans or 12 degrees BTDC for an auto trans. I usally set these case settings to at least 8 to 12 degrees BTDC depending on locale condistions. If your car happens to have Calif emissions that changes some of the settings too.

4. With the engine now warmed up to operating temps and the choke is fully open. Set idle mixture screw to the lean best idle. This done by first setting the mixture screw to the highest Idle RPM using a Tach / Dwell meter and next you would turn the mixture screw inward an adistional 1/4 turn (leaner).

5. Last you set the Curb idle to 500 to 575 RPM for a manual trans, or 550 to 600 RPM for an auto trans its in drive with parking brake set, this will usually be 50 to 100 RPM higher when trans is in Neutral or Park.

The order of the settings can make a difference to the final tune up settings, this is why the carb settings are always the last thing. Hope that is of some help. Good luck

The fan shroud came in today and I did a mock-up fit test before taking out radiator and everything else to install it. I don't think it'll work because I don't have that much space between the radiator and the belts and fans. The shroud is around 3.5 inches wide, and I have 3 inches of space before it hits the power steering pump (I have attached pictures in the link below, as well as the pictures of my whole set up). I lined it up flush against the radiator and I could still see that even if I take everything apart and install, it will still not clear the power steering pump. I also will have to cut a opening for the bottom hose to fit correctly...

I don't want to hack up the shroud for it to fit because I don't really see this one fitting at all. Am I doing something wrong here or will this shroud simply just not work for my application?

https://photos.app.goo.gl/5guM2zgz5wWYZLUq9

Thanks,

That really sucks, your not doing anything wrong that aluminum radiators core must be quite a bit thicker than the stock 200 copper / brass radiator. With a 289 / 302 V8 it would only a 1/2 of an inch shorter in lenght than the 200 six. So unles you could slide the engine backwards by modding the engine mounts a little and or moving the radiator forward an inch that shroud isn't going to work witout radically cutting a 3/4 to 1 inch section out of it. In fact with that little of clearance / distance between the radator core and the V belt & pulleys that shroud wouldn't even fit with a V8 that it' was designed for. Sorry except for the 1970's Maverick / Comet sixes (they are shorter in height) otherwise i don't know of another shroud option. If you want try building your own shroud use that one for the mock up and basic measurements removing about an inch from the transition/ funnel area next to were it bolts against the core. Your Mustangs engine compartment sure is detailed nicely.

Thanks! Just wish it ran as good as it looks :rolflmao: I'm going to go ahead and tackle tuning and making sure the timing is right on the engine. I feel that my idle RPM's are too high so my timing might be off as well as some carb settings. I definitely didn't know about the larger spark plug gap sizes for petronix ignition systems, which is what I have installed in the distributor instead of points. Let you know what I find...

yep, easy stuff 1st, & stuff where 1 lill change can contribute to many other benies.

"...* radiator (sz, clean?, construction, materials - I like ol style copper)...."
looks like "an 8 row radiator". One or 2 row is fine, oem is best.

So, yeah, timing, thermostst, flush, correct 50/50%, etc. How hot does it get again?
Only in traffic, correct? Blead out air (in H.core too).
geta $8 infared hand held & point it arround, report back here...
New radiator might B last (not 1st) on my above list...along w/a 'pusher' infrnt of it...