What are the indications that a Mazda R2 Diesel Cylinder Head Assembly sold by a Surplus Company has no cracked or overheated.

https://autospruce.com/mazda-r2-2-2l-diesel-engine-problems-reliability/

Yes, if there's white smoke coming out the exhaust the engne is burning coolant it has to get into the combustion chamber via a broken head gasket, a cracked head or a cracked block. A simple leak down test will identify the problem cylinder. I hope this helps. Take care.

no engine told at all or country.
sold all over earth, with many engines sued.
cracks happen for 2 reasons
overheating the engine
or using only water for engine coolant, in winter , it turns to ICE cracks the engine block and heads in 1/2 total destruction easy as pie done wrong.
recalls, TSB pages
USA car, at the makers TSB pages , 1 hit only on word CRACK
quoted:
TS 35 12103, Special Coverage Extension for Specific Crack(s) in the Cylinder Head

SPECIAL COVERAGE EXTENSION FOR SPECIFIC CRACK(S) IN THE
CYLINDER HEAD.
MODEL(S): GRAND VITARA (JB) WITH 2.4L ENGINE
YEAR: 2009 (START OF PRODUCTION THROUGH JULY, 1 2009)
Engine overheating with possible Internal Engine Noise. The engine coolant
may leak from the cooling jacket into the Camshaft Housing of the Cylinder
Head. There will be no external coolant leak and there will likely be evidence
of coolant contamination in the engine oil.
CAUSE: Suzuki has determined that certain 2009 Grand Vitara vehicles may develop
a crack(s) between cylinder head bolt(s) and casting plug(s).
CORRECTION: A special coverage extension will apply for vehicles beyond the basic
warranty limits. The coverage allows repairs to be made for customers at no
charge for parts and labor up to 7 years or 102,000 miles, whichever comes
first, from the date of first use, at authorized Suzuki service points. Cracks in
locations other than the specified areas of the cylinder head do not qualify for
the coverage extension."

Follow the link mazda b2500 torque sequence and settings cylinder head td bolts

Water in the oil means one of 3 things:

1) Cracked or warped cylinder head
2) Cracked engine block
3) Blown head gasket

Blown head gasket is the best you can hope for. And cracked or warped cylinder head is next most likely. A cracked engine block is least likely of the three. Have you noticed anything unusual, heard any noises? And has the car overheated really badly?

Mazda B2200, B2500 and B2600 (6th Generation).

In model year 1998, Mazda B series renews its own international markets. Production at the plant AutoAlliance Thailand began in May 1998. This model is also sold as the Ford Ranger in Europe and Asia, and the Ford Courier in Australia and New Zealand. Production started this year in the factories of companies AutoAlliance Thailand and Ford Motor Philippines. Versions CKD are also assembled in South Africa, Ecuador and Colombia.

The van is sold in over 130 countries under a variety of names. Along with the emblems of Fighter and Ranger in Southeast Asia (except Singapore, which served as the flagship models Proceed Japan), was sold as the Mazda Bounty and Ford Courier in New Zealand, Mazda Bravo in Australia, and Mazda Drifter in South Africa.

Engine options:
2.2 L 2.2 L (2.184 cc) 85 hp (63 kW)
2.5 L (1.998 cc) turbo diesel 118 hp (88 kW)
2.6 L (2.606 cc) 121 hp (90 kW)

Fig. Tighten the exhaust manifold bolts in 2 stages

To install:

1. Clean the mating surfaces on the exhaust manifold and the cylinder head.
   
2. Install a new gasket and the exhaust manifold. Torque the bolts in sequence as follows:
   1. 16 ft. lbs. (23 Nm).
      
   2. 59 ft. lbs. (80 Nm).

Hope helps.

You have either blown out the head gasket or cracked the cylinder head itself. You will need to remove the cylinder head and at a minimum replace the head gasket. Inspect head surface after dis-assembly to verfiy that no cracking is present.

Yes if you have a cracked or warped cylinder head or a cylinder head gasket blown problem this will cause your engine to over heat.

Well, just remember a head gasket that fails is a victim, and not a cause. Something else is not right, like head warped. you need to find that issue or gasket will fail again real soon.

gas or oil in radiator is usually strong indication head gasket is blown, not good idea to keep running it like it is.