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What is causing my overheating issue?

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boeingpilot

boeingpilot

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I've been attacking this problem for a while now. The car ran great all summer and fall and then all of a sudden started overheating. If the car is going down the road it's fine. As soon as I hit traffic or a stop light the temp starts to climb. I've replaced the thermostat, radiator cap and water pump. I thought it may be a bad voltage regulator, but the Hayden electric fan is coming on which it never does, and when I slowly back the radiator cap off the coolant is frothy and bubbly (both technical terms, BTW)so there is definitely something up. I'm at the end of my rope and about ready to trailer it to the shop. Any thoughts?
 
This is quite simple.
You...like most most reading this forum...
own a Triumph! Thts where the party starts.
Gil NoCal
 
Frothy coolant suggests a head gasket leak or a cracked head. There is a simple test that any radiator shop can perform for you (mine charged me $18 in 2005), or you can pick up the tool and do it yourself. I managed to find a lightly used tool & partial bottle of chemical on eBay for $25 so now I can do it whenever I want.

Another possibility might be blocked radiator tubes. Have you tried having it rodded out?

Of course there are a zillion other things it could be. On my TR3A, I eventually discovered that the radiator tubes were not in good thermal contact with the fins, and so were not conducting heat from the water to the air very well. My radiator shop did not notice the problem until I asked about it, but a recore solved the problem.
 
What does the test determine? Radiator blockage or head/gasket problems? This cooling issue literally started from one day to the next. It ran great all summer and fall and then started acting up.
 
The test is to determine if there are exhaust gases flowing into the coolant. If there are, then there is some problem with the head gasket, or a crack.
 
boeingpilot said:
This cooling issue literally started from one day to the next. It ran great all summer and fall and then started acting up.
Click to expand...
That would make me even more suspicious of a problem with a head gasket (or possibly crack). Otherwise, I'd also have suggested a thorough flush of the block as well as radiator. That still can't hurt, but neither tends to instantly clog up!
 
It's a simple test. The chemical changes color if there is carbon dioxide in the coolant. If I remember from years ago, if it stays blue, it's fine. If it turns yellow, get out the compression gauge and start cranking to be sure.
 
Before you tear to much down, be sure to take a look at the lower radiator hoses. They can look fine at idle, but suck closed when the engine revs...

Just give them a good squeeze to see if they are both still rigid.
 
Brosky said:
If I remember from years ago, if it stays blue, it's fine. If it turns yellow, get out the compression gauge and start cranking to be sure.
Click to expand...
That's right, except the compression gauge part. The chemical can detect leaks that the compression gauge will miss. For example, a gasket that is just starting to go may only leak at WOT when pressures are highest, and not at all under the much lower pressures of cranking.

https://www.blockchek.com/
 
Not exactly what I meant Randall. I agree with you, but I was just trying to isolate where the leak MAY be coming from after the chem test showed it was there.

I've done the chemical tests that showed a problem but the owners felt it was incorrect. And the engine still had good compression readings, but a week or so later, the white smoke was billowing out of the the tailpipes.

The compression may not always show up, but when it does after the chemicals, there is no denying a problem in there.
 
I guess I still don't follow you, Paul. I've had engines where the head gasket was clearly leaking under pressure, but ran for months without "white smoke".

In fact, I'm pretty sure a bad head gasket (and/or warped head) is the problem with the Stag sitting in my driveway at the moment. I spent several months fiddling with new radiators, fans etc. before finally having the test done. Bought my own tester so I could experiment with various "block seal" products (none of which helped, BTW).

So, if the tester shows a problem, and the compression check doesn't, the problem is likely a blown gasket or cracked head. If the tester shows a problem and the compression check agrees, the problem is likely a blown gasket or cracked head. I still can't see any point in doing a compression check after the "block tester" says you have combustion gases in the radiator. Once the chemical turns yellow, you might as well just start removing the head(s).
 
I've got good, even compression on all 4 cylinders, and it only blows a little white smoke on initial start up. I called the shop and described the symptoms. Cracked head and/or block was the first thing out of his mouth. I have an appointment on Tuesday to have the above mentioned test done. We shall see what we shall see.
 
boeingpilot said:
We shall see what we shall see.
Click to expand...
As my old friend Ed Hart used to say, "We will know in the fullness of time"....
Good luck!
 
Randall, I think we are saying the same thing, only differently. I know and you know that once the color goes yellow, you will be pulling the head(s), either now or later. I was just stating that there was a time when I did a compression test after to prove the point and the compression showed to be good. So they took the car and drove the heck out of it for a week and then it returned blowing white smoke. At that point there was no doubt that the diagnosis was right in the beginning.

I was saying to clarify the chem test a compression test will usually remove all doubt and will show if it's going between two adjacent cylinders or otherwise.

Now back to our regularly scheduled program.
 
My father's 1968 Spitfire used to overheat, well, the temperature climbed to the hot zone. The way I got the temperature to be normal was to turn on the heat. Maybe your oil is getting thin and causing more friction and heat. We run 20W50 oil in our Spits and after an oil change I no longer had the problem of the car getting hot. =]
 
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