Perkins 4108 coolant flow problem

[beef]

Similar issue to mine after fitting new water pumps (fresh and raw). Put the pre mix coolant in I asked for at local autofactors. On first start climbed to 90c after 10 minutes although I have a 75c thermostat and the overheat alarm sounded. New impeller and pumping water at the exhaust outlet. Wasn't airlocked. Little dickhead had given me regular anti freeze and the big dickhead (me) didn't check the label. Drained the system, put 50/50 mix in, normal service resumed and rock steady at 75c. Schoolboy error but they can happen.

 

[RichardS]

Similar issue to mine after fitting new water pumps (fresh and raw). Put the pre mix coolant in I asked for at local autofactors. On first start climbed to 90c after 10 minutes although I have a 75c thermostat and the overheat alarm sounded. New impeller and pumping water at the exhaust outlet. Wasn't airlocked. Little dickhead had given me regular anti freeze and the big dickhead (me) didn't check the label. Drained the system, put 50/50 mix in, normal service resumed and rock steady at 75c. Schoolboy error but they can happen.

I'm not sure what you mean by "regular antifreeze" but the thermal transfer properties of water and various dilutions of any kind of antifreeze are so similar that I don't think you would notice any difference under normal running conditions. Using pure undiluted antifreeze would, in theory, cause the engine to run slightly hotter if its cooling system was marginal but, once again, in most engines I don't think that there would be any problem from a cooling perspective.

Richard

 

[beef]

Well I can testify that if I use undiluted antifreeze in my 4108 it will run 25c over normal operation temp within 20 mins and the overheat alarm will go off. That's first hand experience with identical engine to OP which may be of more use than the physics text book.

 

[pcatterall]

Well I can testify that if I use undiluted antifreeze in my 4108 it will run 25c over normal operation temp within 20 mins and the overheat alarm will go off. That's first hand experience with identical engine to OP which may be of more use than the physics text book.

That's interesting. It suggests that use at normal dilution will increase the running temp slightly above that of pure water?
Not the issue with mine. The 'infra red' thermometer has been very useful. It seems that I may have had an air lock of some kind but there was an issue with the engine sensor or the engine gauge which although allegedly being centigrade was reading Fahrenheit! Still 'playing' and still trying to get drains out !!

Thanks

 

[beef]

My overheating issue may have more to do with the thicker viscosity of undiluted antifreeze versus a correctly diluted mix rather than thermal cooling properties.

Like the other members who have contributed I would be interested to hear the solution should I encounter identical trouble down the line.

Best of luck, sorry not to be more helpful.

 

[RichardS]

Well I can testify that if I use undiluted antifreeze in my 4108 it will run 25c over normal operation temp within 20 mins and the overheat alarm will go off. That's first hand experience with identical engine to OP which may be of more use than the physics text book.

As you say, it's a viscosity effect .... but It wasn't clear that your term "regular" antifreeze meant "undiluted" antifreeze. As I said, in most engines the overhead is such that even undiluted antifreeze would not cause major overheating under normal operating conditions but in an engine where cooling is marginal because of age or design, then it could lead to problems. Some people deliberately run their engines on undiluted antifreeze without any problems but I would not recommend it.

Richard

 

[pcatterall]

As you say, it's a viscosity effect .... but It wasn't clear that your term "regular" antifreeze meant "undiluted" antifreeze. As I said, in most engines the overhead is such that even undiluted antifreeze would not cause major overheating under normal operating conditions but in an engine where cooling is marginal because of age or design, then it could lead to problems. Some people deliberately run their engines on undiluted antifreeze without any problems but I would not recommend it.

Richard

Age and design sir!! How very dare you?? this is a 4108 we are discussing

 

[SVBewildered]

I am having a problem of overheating at start up. Fresh Water Pump, Rawater pump and thermostat all new. Was running well at 170F. Now on start up overheats. Headert tank very hot and water pushed out via the filler cap. Stop engine, open bleed screw on headed tank, top up coolant. Start engine agin and the same happens a second time. Follow procedure again and start engine which runs with no problem. Running at 1200RPM for two(2) hours, shut down, check coolant level which is run OK. Leave overnight and start again with the same problem. Have considered this may be thermostat related but have removed and checked and it opens are the correct temperature. Considering removing thermostat and fitting a washer to restrict flow to see what happens. Comments please. Richard Naylor, S, V. Bewildered,

 

[SVboatless]

I know this is too late for the posters here but for anyone else with this issue, we solve the same issue.

Problem statement: Perkins 4.108 overheats after changing the coolant pump. (It went to 185 F before we cut the engine.)
Reason: The engine on this sailboat has a water heater tank in the coolant loop (typical on sailboats). Good for warm shower BUT creates an airlock if you drain the coolant too far, for example by replacing the coolant pump as in our case ant the poster before.
Solution: On the engine I worked on the one hose from the water heater tank went to the oil cooler, the other when to the top of the engine. The top of the engine had a pipe sticking up about 6 inches that the hose connected to. I do not know if this is a typical configuration. We disconnected the hose that went to the top of the engine pipe. We noticed you had to lower the hose to below the header tank before we saw the coolant. We raised the hose to the same level as the fitting we disconnected it from, and put a funnel in the hose, and then added coolant until it came out of the fitting on top of the engine. It took, I would guess, between 1 and 2 pints. We then reconnected the hose.
Outcome: engine heated up to 160 F and stayed there exactly. i.e. we had fixed this issue.

Thanks to some random post I saw that mentioned water heater tanks can be a problem with airlocks.
I hope this helps someone else, if it does post a reply to help the next person with this issue.

 

[Refueler]

There is a note in the mnaual for the 4.108 which says to make sure the correct type of thermostat is fitted. "Certain engine applications have an external bypass which incorporates a thermostat with a bypass blanking valve. This valve closes the bypass port as the thermostat opens ."

Its strange that - as my 4-107 runs without thermostat and is fine .... and I know that it has similar 'bypass' ...