Jump to content

Isuzu 42 thermostat


Featured Posts

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

Link to comment
Share on other sites

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 by bigste
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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 by Tony Brooks
Link to comment
Share on other sites

  • 2 weeks later...

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

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.