Muffler/engine hot

[Meggypeggs]

Wondering if anyone could assist.

I recently moved over to a stock setup from dual carbs to a single setup and having problems with the engine heating, especially the muffler. To the point that paint is bubbling at the back! Done the whole dipstick thing and occasionally it’s too hot to hold after a second.

Beetle is a 71, 1600 dual port and with a 34 pict 3 installed. I replaced the 009 with a 34 vacuum. Ever since the switch the heating has occurred. Muffler is stock and a VW specialist garage has undergone a service as in valves/points etc. Tinware is all fine and no holes. I have even put on a different carb thinking it was the carb but it still gets hot after 15 mins.

Has anyone else had this issue? Or know what’s causing the heat?

Any help is appreciated.
Thanks
M

[Igpoe]

Recheck the timing first. Then your carburetor adjustment may be off. Check to see that air is flowing freely through the fins all-around and there is no obstruction in front of the fan. Make sure the oil cooler isn't being bypassed. Recheck the valve adjustment. Is your oil too thick? Many things can contribute to overheating. Don't forget to keep a tight belt!
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'73 super.

[beetlenut]

Valves, timing, carb adjustment and oil weight. I had this issue with a newly rebuilt engine. Rechecked and adjusted all those settings, and went to 5w-30 oil, and things cooled down.
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[Meggypeggs]

Appreciate the replies.

Today I checked the timing with a light and checked the valves. They were a bit out so corrected them. However, went to pick my daughter from work which is a 10 minute drive and was hot again when I got there. Sat down until it cooled and drove home. Only thing I’ve not done is the oil. Plus, although it is hot here in the uk I’m still sure it’s overheating. Carb setting seems fine too.

[busdaddy]

[AlmostHeavenWV_VW]

I read over your post a few times, but I don't think you indicated how you discovered this new possible issue. I have a few questions:


What first caused you to decide you were having a heat issue? Poor performance? Misfiring? "pinging" or "knocking" in the engine?

How are you determining the 'heat' issue? What measurement/device/gauge/tool was used?
---if you are basing it off of the so-called 'dipstick test' that's a really subjective and inaccurate way to compare temperatures (as you noted the dipstick is *occasionally* too hot to hold)

What paint is bubbling? Muffler paint? Decklid? Rear apron?

How did you discover that the engine was 'hot' when picking up your daughter? How did you determine it had 'cooled down'?
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1973 Standard Beetle
1600DP AK case
Solex 34PICT3 Carb
Bosch DVDA 205AJ Distributor

[planenut]

If your only major change is the carbs, I'm going with the engine isn't getting enough fuel, and it's running lean. You may need a larger main jet.

[vwoldbug]

Does the fan shroud have the flaps and is there a thermostat present. Make sure the flaps aren't stuck closed.

[Eric&Barb]

Check that the cooling fan does not have something sucked into it. Do make sure the engine is off when you reach around to the front of the fan shroud when doing that.

Get a meat or candy thermometer with 150mm minimum long probe and not much bigger than 25mm diameter dial face so it can fit down next to the case in the dipstick hole.

Trying to test heat by hand is bogus. Barb can not handle hot cups/bowls of food with her hands, where I can easily lift the same container with my bare hands and just get to eating right off the bat.

Also if you have the dog house fan shroud you need the bigger DH cooling fan and crankshaft pulley. Using earlier smaller ones will cause cooling problems. Check and verify, no "seems".
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In Stereo, Where Available!

[tasb]

All of the above and exactly what distributor are you running?
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1961 (October)Single Cab- Road Trip Workhorse

[challomoner]

My 1600 sp was doing this when I first bought it, advance mechanism was stuck.

[Tim Donahoe]

Mufflers get hot. Real hot. If it’s fairly new and you didn’t remove all the pre-paint from the manufacturer and re-paint it with a heat-proof paint, then the original paint is apt to bubble.

The old holding-the-dipstick-by-the-hand trick is just plain silly. On a hot day, on a hot highway run, you really don’t want to hold onto a dipstick that may have just been immersed in oil which is a normal 210-220 degrees Fahrenheit.

Regardless, you may have a problem. Check your advance at 2500-3000 rpm’s to see if it’s over advancing. After a nice run, check your oil temperature with a thermometer to get the actual temperature.

If you really have a problem, also take the advice already given in this thread.

Tim
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Richard O'Brien

[joemama]

Maybe post a pic of where the paint is bubbling. With dual carbs you did not have heat risers, with the stock setup you do. Often the paint in that area burns off. This doesn't necessarily mean that its running hot.

[Paul Windisch]

A couple other things to check.

1) If it has the original decklid, it may not provide enough cooling air. A stock '71 decklid had two columns of air vents, and the later Dual Port engines with doghouse coolers utilized four. It is possible your dual port and original decklid are not playing well together.

2) Check the belt to make sure it's not slipping. If it is, your fan isn't always spinning as fast as it should.
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1984 Mexican Beetle
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-034 SVDA Distributor

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[Igpoe]

Meggy, have you found the problem? Take a photo of your engine compartment and post it in this thread. We, the thousands, may see an issue relating to your problem that is yet to be considered. Happens every day.
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'73 super.

[lboos]

Why don't you invest in a infrared thermometer gun? there cheap. then you won't have to guess what is to hot. and after a normal trip and before you shut off the engine you can check the temp. on the cly's, engine block, muffler etc. and dip stick.
Then others might compare there engine heat with you to kind-of get an idea of what is to hot, and what is normal.

I will be glad to give you the temp. on both my bug's [71-72] if you get a temp. gun and let me know what part of the engine you took the temp. from.

Best if done here.

[VW_Jimbo]

Not trying to sound bothered, but you should really have a means to prove your hypothesis. Fixing cars is not a guessing game. It is a science. There are several variables all dependent on one another for proper operation.

So, pick up an IR thermometer and verify your hypothesis!

Stop guessing. Let’s get some real data and determine what the issue is, if there even is one.
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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!