'67 Riviera overheating

After replacing my temperature sending unit on my 67 Riviera about 2 weeks ago, the gauge would usually sit above the halfway mark - approximately of the way up. Once in a while it would creep even closer to the right. I decided to change my thermostat. When I took apart the housing and removed the old thermostat, I thought I had found my problem. The thermostats copper pellet, spring and valve had been cut offso water/coolant were constantly being sent to the water pump and radiator at the same time.

Here are some details on the cooling system:

- New water pump
- New fan clutch
- New temp sending unit
- New thermostat


I had a few problems getting the new stat installed without the gasket leaking when the radiator was filled - thermostat was slipping a bit out of its groove as I was bolting on the housingbut I realized my mistake today and installed it with a new gasket from Napa without any leaks. Used Permatex Hylomar on the gasket. Only a few minutes after starting the motor the temp gauge was nearly all the way to the right. I turned it off and checked my radiator. The cap was already VERY hot. Then the thermostat housing started to vent pressure and leak fluid.

My questions are:

1) Why would someone remove the thermostat? My guess is that the last guy who owned the car knew that the rad wasnt cooling sufficiently and wanted constant flow through itdoes this assumption make sense?

2) Should I put in a new radiator? I believe it has the original 3 core.


Thanks,
Dan
Austin, TX

 

hmmm

Put in a 4 core radiator...that helped me tremendously. - well worth the 170 bucks IMO.


Also, how old is the radiator cap? It could be bad. Have you flushed the system? Sounds liek there is a clog somewhere.

 

Is the new thermostat opening? If not that will cause it to overheat real quick. I have had brand new ones that didn't work right on several occasions. I'd try putting it in boiling water to verify it's opening.

 

Did you run it with the cap off until the Tstat opened to purge the air?

 

Thanks for the replies!

After filling the radiator, I started the engine without putting the cap on. The coolant level in the radiator quickly dropped as air escaped from the block. I added some coolant to bring it up to level again. A few seconds after that, the coolant started to pour out of the radiator fill hole and the overflow hose. I let the engine run for a few seconds more than looked at the temp gauge on the dash. It was almost all the way to the right at that point. I turned it off then and a few seconds later the thermostat housing started to vent steam then leaked coolant.

I'm guessing that the thermostat opened if the coolant got that hot in the radiator. One thing I didn't mention in my first post is that when I drained the radiator and block, there was about 6 inches of coolant left on fill side of the radiator.

Dan

 

I'm thinking obstruction(s) in the system and/or radiator. Backflush maybe?

My 67 Riv had the original 3-row, which eventually clogged up and started overheating. Solution: new 3-row, which does fine. Tried to replace it with 4-row but when I did the radiator top cover wouldn't fit it. Unless you're towing or live in the desert, three should be okay; GM designed it this way in the first place.

Good luck.

 

I agree. I spoke to someone at a radiator shop here in town.
They work on a lot of classics and customs, so he's fine with me bringing in a new radiator from my own parts source. He suggests taking a look at my radiator first to see if it can be recored. If not, then we'll put in a new one. They can also flush the system using an air compressor and water (no chemicals).

What's the general opion on having a rad recored versus putting a new one in? Is it worth the cost savings, or just a short term solution?

Thanks,
Dan

 

Re-core vs New Radiator

The supposed advantage of recoring is the heavier gage construction of the original end tanks, as opposed to new construction. As the legend goes, they just don't build the end tanks today as well as they did in the 1960's; not as thick, poorer quality in general. This was demonstrated to me by "thunking" respective old and new tanks with my finger, which produced a decidedly more solid sound in the older tanks compared to a relatively tinny one in the new radiator.

Of course, the radiator shop guys showed me this, which you can assume is at least somewhat influenced by the additional work that goes to them in a re-core, vice a simple installation of an aftermarket job. That's okay, but a grain of salt is probably appropriate.

Anyone else have an opinion on this one?o No:

 

And by the way I had mine recored - no troubles to date!:TU:

 

Danny Who is doing your radiator?

 

Are you certain the thermostat is not in backwards? An engine venting from the thermostat housing indicates no flow. The spring should be towards the engine. I've seen this happen more than once...hope it's something that simple.

 

Yep, thermostat's installed properly - pellet in the block. The fact that the radiator won't drain all the way when I open the draincock (located at the very bottom of the rad) and the block at the same time, makes me believe that it's clogged.

Phil, I was going to use City Radiator on South Congress. They've been around since '75 and I've heard good things about them. Do you know about their work?

Erik, how long have you been running with the recored radiator? Personally, I'd prefer keeping my original radiator both because of better construction and for the cost savings.


Thanks,
Dan

 

No idea on There work danny! I would reccomend crower radiator in pflugerville. however it looks like you got things worked out. Danny Are you free on september 27th have a nice little buick event happening give me a pm if intrested.

 

Thanks for the info on Crower Phil. I'll probably use City since I've heard good things and they're only a few miles from my place. I'm going to have the car towed, hopefully at no charge through my wife's AAA membership.

I won't be around on the 27th, I'll be out of the country from the 23rd until October 22nd. Where is the Buick event? Is it a yearly thing? I need to start going to some meets. Someone told me the other day that the Saturday night meet in Round Rock is now in Oak Hill, near the Y. That's a short drive from my place, so I can check that out finally.

Dan

 

danny there is one in oak hill and one in roundrock! the round rock one is still there tell your buddies. The oak hill one is pretty good also.

 

Cool, thanks Phil.

I met this guy with a '55 Chevy who told me about the Oak Hill meet. Turns out he's a woodworker, works on boats mostly, but he can hook me up on new console pieces for the Riviera. I haven't checked out his shop yet, but I can let you know about it you're interested. I was going to do this myself, but I'll check out what he's got first.

Dan