Isuzu 42 thermostat

[Rob99fla]

Hi. I have replaced the head gasket on my Isuzu 42 (see previous post). It defiantly was blowing upon inspection (due to a leaking hose and loss of coolant) We had the head skimmed, new bolts and genuine parts. The engine seems to be running fine except it's slow heating up. I suspect the thermostat is possibly sticking open as I remember the RCR engineer last summer showing me how the thermostat opens and closes by the temperature gauge. My question is, where do I get a cheaper thermostat other than the £50 plus genuine one I've seen on EBay. Are thermostats like filters. Common parts but large variation in price? Cheers. Rob

[bigste]

don't know your particular engine but yes thermostats are like filters, everybody makes them. What's more they are two a penny. Taking it to any motor factors, not Halfords, will easily match it up. Better than that, someone on here may know a particular car that uses the same.

 

edit: If you type Isuzu 42 thermostat into ebay you get some surprising results.

Edited May 1, 2016 by bigste

[b0atman]

Check out pricing at Anglo Welsh they use the Isuzu in their older boats and I believe newer engines are based on Isuzu and some other make.I just had a new oil pressure switch fitted at Great Haywood £59 all in would of been a lot more on my Astra car with a Isuzu engine.

[andyb116]

Be carefull if you get an automotive thermostat, even though they look the same, they tend to have a higher opening temperature than a marine one.

[Tony Brooks]

Be carefull if you get an automotive thermostat, even though they look the same, they tend to have a higher opening temperature than a marine one.

 

That really should not be a problem engine wise on a tank or heat exchanger cooled boat. The original idea of low temperature thermostats in marinisations was from the days of direct raw water cooled engines when running at much more than about 60C would fur up the hotspots in the cylinder head with lime scale or salt. As heat exchanger, tank, or keel cooled system are closed systems just like a car running them as hot as a car should be fine.

 

The same is not true for the domestic hot water that is heated by the calorifier. Its hot enough to be very uncomfortable with a 62C stat, it could be downright dangerous with an 88C one. That is unless a thermostatic mixing valve is in use.

 

Of course this assumes that the cooling system is adequate, which many narrowboat systems are not, but even then a cooler thermostat only covers up any problems for a while.

 

Anyway the temperature should be stamped on the old and new thermostat.

 

What is perhaps of more importance is that the OP does not get sold the wrong type of thermostat. There are three types. A normal one, a bypass thermostat that has a big washer thing underneath it and a bypass stats that has an extra "band" around the body. Fitting the wrong one is likely to compromise the cooling system.

Edited May 1, 2016 by Tony Brooks

[bigste]

Opening temps are stamped on the thermostats so there is no problem in using 'car' thermostats.

[Rob99fla]

I'm still looking for this thermostat. Motor factors are trying to help, cross referencing the part. I believe these engines (Isuzu) are used mainly in plant machines (dumper trucks etc) these days. I just can't believe it is so difficult to find the right thermostat. I just can't bring myself to pay £53 for a genuine one. Can anyone help again? Many thanks. Rob

[Tony Brooks]

This must be very special, lets have a photo please.

[Rob99fla]

 

Hi. Here are some pictures of the thermostat. Looks pretty standard to me. Cheers. Rob

[Tony Brooks]

Yes - perfectly standard 82 degree bypass thermostat unless it is an odd diameter.

 

As I said before the exact temperature should not be an issue, near enough will do but I would tend to go down rather than up.

 

Sorry I have no idea what car to look for but maybe a Landrover.